Method for transmitting signal in wireless communication system supporting unlicensed band, and device supporting same

ABSTRACT

The present disclosure relates to a method for transmitting a signal in a wireless communication system supporting an unlicensed band, and a device supporting the method. The method according to an embodiment of the present disclosure may comprises: performing a channel access procedure for multiple frequency bandwidth units included in an activated bandwidth part; and transmitting a data signal through an unlicensed band based on the channel access procedure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/KR2019/001522, filed on Feb. 7, 2019, which claims the benefit ofKorean Application No. 10-2019-0003572, filed on Jan. 10, 2019, KoreanApplication No. 10-2018-0137543, filed on Nov. 9, 2018, KoreanApplication No. 10-2018-0092789, filed on Aug. 9, 2018, U.S. ProvisionalApplication No. 62/663,196, filed on Apr. 26, 2018, U.S. ProvisionalApplication No. 62/658,515, filed on Apr. 16, 2018, and U.S. ProvisionalApplication No. 62/627,674, filed on Feb. 7, 2018. The disclosures ofthe prior applications are incorporated by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates to a wireless communication system, andmore particularly, to a method of transmitting a signal in a wirelesscommunication system supporting an unlicensed band and device forsupporting the same.

BACKGROUND ART

Wireless access systems have been widely deployed to provide varioustypes of communication services such as voice or data. In general, awireless access system is a multiple access system that supportscommunication of multiple users by sharing available system resources (abandwidth, transmission power, etc.) among them. For example, multipleaccess systems include a Code Division Multiple Access (CDMA) system, aFrequency Division Multiple Access (FDMA) system, a Time DivisionMultiple Access (TDMA) system, an Orthogonal Frequency Division MultipleAccess (OFDMA) system, and a Single Carrier Frequency Division MultipleAccess (SC-FDMA) system.

As a number of communication devices have required higher communicationcapacity, the necessity of the mobile broadband communication muchimproved than the existing radio access technology (RAT) has increased.In addition, massive machine type communications (MTC) capable ofproviding various services at anytime and anywhere by connecting anumber of devices or things to each other has been considered in thenext generation communication system. Moreover, a communication systemdesign capable of supporting services/UEs sensitive to reliability andlatency has been discussed.

As described above, the introduction of the next generation RATconsidering the enhanced mobile broadband communication, massive MTC,Ultra-reliable and low latency communication (URLLC), and the like hasbeen discussed.

SUMMARY

The object of the present disclosure is to provide a method oftransmitting a signal in a wireless communication system supporting anunlicensed band and device for supporting the same.

It will be appreciated by persons skilled in the art that the objectsthat could be achieved with the present disclosure are not limited towhat has been particularly described hereinabove and the above and otherobjects that the present disclosure could achieve will be more clearlyunderstood from the following detailed description.

The present disclosure provides a method of transmitting a signal in awireless communication system supporting an unlicensed band and devicefor supporting the same.

In an aspect of the present disclosure, provided herein is a method oftransmitting a signal by a transmission node in a wireless communicationsystem supporting an unlicensed band. The method may include performinga channel access procedure for a plurality of frequency bandwidth unitsincluded in an active bandwidth part and transmitting a data signal inthe unlicensed band based on the channel access procedure.

In an embodiment, the data signal configured based on a frequencybandwidth greater than a single frequency bandwidth unit may betransmitted in at least one frequency bandwidth unit determined by thechannel access procedure.

In an embodiment, the data signal may be configured in the frequencybandwidth greater than the single frequency bandwidth unit according toa frequency-first mapping method.

In an embodiment, the data signal may include a plurality of blocksdefined based on a plurality of frequency intervals and at least onetime interval.

In an embodiment, the data signal may be mapped on a block basisaccording to the frequency-first mapping method.

In an embodiment, the signal transmission method may further includetransmitting a demodulation reference signal (DM-RS).

In an embodiment, the transmission start time of the DM-RS may bedetermined according to a predetermined method.

In an embodiment, the predetermined method may include at least one ofdetermining the transmission start time of the DM-RS based on the starttime of the channel access procedure and the transmission start time ofthe data signal or determining the transmission start time of the DM-RSby shifting the location of a symbol to which the DM-RS is mapped basedon the channel access procedure.

In an embodiment, transmitting the data signal may include transmittingthe data signal by puncturing the data signal in at least one frequencybandwidth unit determined to be busy by the channel access procedure.

In an embodiment, the signal transmission method may further includetransmitting the punctured data signal in at least one slot after a slotin which the data signal is transmitted.

In an embodiment, the at least one frequency bandwidth unit fortransmitting the data signal may be determined to be idle by the channelaccess procedure.

In an embodiment, the signal transmission method may further includetransmitting information on the at least one frequency bandwidth unitdetermined to be busy by the channel access procedure.

In an embodiment, the data signal may include a transmission block witha different redundancy version (RV) for each of the plurality offrequency bandwidth units.

In an embodiment, different RVs may have different RV indices.

In an embodiment, an RV index may be determined according to apredetermined method.

In an embodiment, the predetermined method may include at least one ofdetermining the RV index based on scheduling downlink controlinformation or determining the RV index based on a function related tothe plurality of frequency bandwidth units.

In an embodiment, the frequency bandwidth greater than the singlefrequency bandwidth unit may be related to the active bandwidth part.

In another aspect of the present disclosure, provided herein is acommunication device in a wireless communication system supporting anunlicensed band. The communication device may include a memory and atleast one processor configured to control the memory.

In an embodiment, the at least one processor may be configured toperform a channel access procedure for a plurality of frequencybandwidth units included in an active bandwidth part and transmit a datasignal in the unlicensed band based on the channel access procedure.

In an embodiment, the data signal configured based on a frequencybandwidth greater than a single frequency bandwidth unit may betransmitted in at least one frequency bandwidth unit determined by thechannel access procedure.

In an embodiment, the data signal may include a plurality of blocksdefined based on a plurality of frequency intervals and at least onetime interval.

In an embodiment, the data signal may be mapped on a block basisaccording to a frequency-first mapping method.

In an embodiment, the at least one processor may be configured totransmit a DM-RS.

In an embodiment, the transmission start time of the DM-RS may bedetermined according to a predetermined method.

In an embodiment, the predetermined method may include at least one ofdetermining the transmission start time of the DM-RS based on the starttime of the channel access procedure and the transmission start time ofthe data signal or determining the transmission start time of the DM-RSby shifting the location of a symbol to which the DM-RS is mapped basedon the channel access procedure.

In a further aspect of the present disclosure, provided herein is atransmission node in a wireless communication system supporting anunlicensed band. The transmission node may include a transmitter, areceiver, and at least one processor configured to control thetransmitter and the receiver.

In an embodiment, the at least one processor may be configured toperform a channel access procedure for a plurality of frequencybandwidth units included in an active bandwidth part and transmit a datasignal in the unlicensed band based on the channel access procedure.

In an embodiment, the data signal configured based on a frequencybandwidth greater than a single frequency bandwidth unit may betransmitted in at least one frequency bandwidth unit determined by thechannel access procedure.

It is to be understood that both the foregoing general description andthe following detailed description of the present disclosure areexemplary and explanatory and are intended to provide furtherexplanation of the disclosure as claimed.

As is apparent from the above description, the embodiments of thepresent disclosure have the following effects.

According to the embodiments of the present disclosure, a method oftransmitting a signal in a wireless communication system supporting anunlicensed band and device for supporting the same may be provided.

In particular, according to the embodiments of the present disclosure,even when data is not transmitted in some frequency bandwidths due tofailure in a channel access procedure (CAP), data transmission in theremaining bandwidths may be guaranteed, thereby supporting efficientretransmission.

It will be appreciated by persons skilled in the art that the effectsthat could be achieved with the present disclosure are not limited towhat has been particularly described hereinabove and other advantages ofthe present disclosure will be more clearly understood from thefollowing detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the present disclosure, provide embodiments of thepresent disclosure together with detail explanation. Yet, a technicalcharacteristic of the present disclosure is not limited to a specificdrawing. Characteristics disclosed in each of the drawings are combinedwith each other to configure a new embodiment. Reference numerals ineach drawing correspond to structural elements.

FIG. 1 is a diagram illustrating physical channels and a signaltransmission method using the physical channels according to embodimentsof the present disclosure.

FIGS. 2A and 2B are diagrams illustrating radio frame structures.

FIG. 3 is a diagram illustrating frame structure type 3.

FIG. 4 is a diagram illustrating a slot structure in the LTE system towhich the embodiments of the present disclosure are applicable.

FIG. 5 is a diagram illustrating a downlink subframe structure in theLTE system to which the embodiments of the present disclosure areapplicable.

FIG. 6 is a diagram illustrating an uplink subframe structure in the LTEsystem to which the embodiments of the present disclosure areapplicable.

FIG. 7 is a diagram illustrating a radio frame structure in a new radioaccess technology (NR) system to which the embodiments of the presentdisclosure are applicable.

FIG. 8 is a diagram illustrating a slot structure in the NR system towhich the embodiments of the present disclosure are applicable.

FIG. 9 is a diagram illustrating a self-contained slot structure in theNR system to which the embodiments of the present disclosure areapplicable.

FIG. 10 is a diagram illustrating a resource element group (REG)structure in the NR system to which the embodiments of the presentdisclosure are applicable.

FIGS. 11 and 12 are diagrams illustrating representative methods ofconnecting transceiver units (TXRUs) to antenna elements.

FIG. 13 is a schematic diagram illustrating a hybrid beamformingstructure from the perspective of TXRUs and physical antennas accordingto an example of the present disclosure.

FIG. 14 is a schematic diagram illustrating a beam sweeping operationfor a synchronization signal and system information in a downlinktransmission procedure according to an example of the presentdisclosure.

FIG. 15 is a schematic diagram illustrating a synchronizationsignal/physical broadcast channel (SS/PBCH) block applicable to thepresent disclosure.

FIG. 16 is a schematic diagram illustrating an SS/PBCH blocktransmission configuration applicable to the present disclosure.

FIGS. 17A and 17B illustrate an exemplary wireless communication systemsupporting an unlicensed band, which is applicable to the presentdisclosure.

FIG. 18 is a diagram illustrating a channel access procedure (CAP) fortransmission in an unlicensed band, which is applicable to the presentdisclosure.

FIG. 19 is a diagram illustrating a partial transmission time interval(TTI) or a partial subframe/slot, which is applicable to the presentdisclosure.

FIG. 20 is a diagram illustrating a signal transmission and receptionmethod between a user equipment (UE) and a base station (BS) in anunlicensed band applicable to the present disclosure.

FIG. 21 is a diagram illustrating bandwidth parts (BWPs) included in aBWP configuration applicable to the present disclosure.

FIGS. 22A and 22B are diagrams illustrating channel occupancy time (COT)sharing between downlink (DL) and uplink (UL) BWPs applicable to thepresent disclosure.

FIG. 23 is a diagram illustrating COT sharing between DL and UL BWPsapplicable to the present disclosure.

FIGS. 24A and 24B are diagrams illustrating BWP(s) applicable to thepresent disclosure.

FIG. 25 is a flowchart illustrating a UE operation method in anunlicensed band applicable to the present disclosure.

FIG. 26 is a flowchart illustrating a BS operation method in anunlicensed band applicable to the present disclosure.

FIG. 27 is a block diagram illustrating the configurations of a UE and aBS for implementing the proposed embodiments.

DETAILED DESCRIPTION

The embodiments of the present disclosure described below arecombinations of elements and features of the present disclosure inspecific forms. The elements or features may be considered selectiveunless otherwise mentioned. Each element or feature may be practicedwithout being combined with other elements or features. Further, anembodiment of the present disclosure may be constructed by combiningparts of the elements and/or features. Operation orders described inembodiments of the present disclosure may be rearranged. Someconstructions or elements of any one embodiment may be included inanother embodiment and may be replaced with corresponding constructionsor features of another embodiment.

In the description of the attached drawings, a detailed description ofknown procedures or steps of the present disclosure will be avoidedleast it should obscure the subject matter of the present disclosure. Inaddition, procedures or steps that could be understood to those skilledin the art will not be described either.

Throughout the specification, when a certain portion “includes” or“comprises” a certain component, this indicates that other componentsare not excluded and may be further included unless otherwise noted. Theterms “unit”, “-or/er” and “module” described in the specificationindicate a unit for processing at least one function or operation, whichmay be implemented by hardware, software or a combination thereof. Inaddition, the terms “a or an”, “one”, “the” etc. may include a singularrepresentation and a plural representation in the context of the presentdisclosure (more particularly, in the context of the following claims)unless indicated otherwise in the specification or unless contextclearly indicates otherwise.

In the embodiments of the present disclosure, a description is mainlymade of a data transmission and reception relationship between a BaseStation (BS) and a User Equipment (UE). A BS refers to a terminal nodeof a network, which directly communicates with a UE. A specificoperation described as being performed by the BS may be performed by anupper node of the BS.

Namely, it is apparent that, in a network comprised of a plurality ofnetwork nodes including a BS, various operations performed forcommunication with a UE may be performed by the BS, or network nodesother than the BS. The term ‘BS’ may be replaced with a fixed station, aNode B, an evolved Node B (eNode B or eNB), gNode B (gNB), an AdvancedBase Station (ABS), an access point, etc.

In the embodiments of the present disclosure, the term terminal may bereplaced with a UE, a Mobile Station (MS), a Subscriber Station (SS), aMobile Subscriber Station (MSS), a mobile terminal, an Advanced MobileStation (AMS), etc.

A transmission end is a fixed and/or mobile node that provides a dataservice or a voice service and a reception end is a fixed and/or mobilenode that receives a data service or a voice service. Therefore, a UEmay serve as a transmission end and a BS may serve as a reception end,on an UpLink (UL). Likewise, the UE may serve as a reception end and theBS may serve as a transmission end, on a DownLink (DL).

The embodiments of the present disclosure may be supported by standardspecifications disclosed for at least one of wireless access systemsincluding an Institute of Electrical and Electronics Engineers (IEEE)802.xx system, a 3rd Generation Partnership Project (3GPP) system, a3GPP Long Term Evolution (LTE) system, 3GPP 5G NR system and a 3GPP2system. In particular, the embodiments of the present disclosure may besupported by the standard specifications, 3GPP TS 36.211, 3GPP TS36.212, 3GPP TS 36.213, 3GPP TS 36.321, 3GPP TS 36.331, 3GPP TS 37.213,3GPP TS 38.211, 3GPP TS 38.212, 3GPP TS 38.213, 3GPP TS 38.321 and 3GPPTS 38.331. That is, the steps or parts, which are not described toclearly reveal the technical idea of the present disclosure, in theembodiments of the present disclosure may be explained by the abovestandard specifications. All terms used in the embodiments of thepresent disclosure may be explained by the standard specifications.

Reference will now be made in detail to the embodiments of the presentdisclosure with reference to the accompanying drawings. The detaileddescription, which will be given below with reference to theaccompanying drawings, is intended to explain exemplary embodiments ofthe present disclosure, rather than to show the only embodiments thatcan be implemented according to the disclosure.

The following detailed description includes specific terms in order toprovide a thorough understanding of the present disclosure. However, itwill be apparent to those skilled in the art that the specific terms maybe replaced with other terms without departing the technical spirit andscope of the present disclosure.

Hereinafter, 3GPP LTE/LTE-A systems and 3GPP NR system are explained,which are examples of wireless access systems.

The embodiments of the present disclosure can be applied to variouswireless access systems such as Code Division Multiple Access (CDMA),Frequency Division Multiple Access (FDMA), Time Division Multiple Access(TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), SingleCarrier Frequency Division Multiple Access (SC-FDMA), etc.

CDMA may be implemented as a radio technology such as UniversalTerrestrial Radio Access (UTRA) or CDMA2000. TDMA may be implemented asa radio technology such as Global System for Mobile communications(GSM)/General packet Radio Service (GPRS)/Enhanced Data Rates for GSMEvolution (EDGE). OFDMA may be implemented as a radio technology such asIEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Evolved UTRA(E-UTRA), etc.

UTRA is a part of Universal Mobile Telecommunications System (UMTS).3GPP LTE is a part of Evolved UMTS (E-UMTS) using E-UTRA, adopting OFDMAfor DL and SC-FDMA for UL. LTE-Advanced (LTE-A) is an evolution of 3GPPLTE.

While the embodiments of the present disclosure are described in thecontext of 3GPP LTE/LTE-A systems and 3GPP NR system in order to clarifythe technical features of the present disclosure, the present disclosureis also applicable to an IEEE 802.16e/m system, etc.

1. Overview of 3GPP System

1.1. Physical Channels and General Signal Transmission

In a wireless access system, a UE receives information from a basestation on a DL and transmits information to the base station on a UL.The information transmitted and received between the UE and the basestation includes general data information and various types of controlinformation. There are many physical channels according to thetypes/usages of information transmitted and received between the basestation and the UE.

FIG. 1 illustrates physical channels and a general signal transmissionmethod using the physical channels, which may be used in embodiments ofthe present disclosure.

When a UE is powered on or enters a new cell, the UE performs initialcell search (S11). The initial cell search involves acquisition ofsynchronization to a BS. Specifically, the UE synchronizes its timing tothe base station and acquires information such as a cell identifier (ID)by receiving a primary synchronization channel (P-SCH) and a secondarysynchronization channel (S-SCH) from the BS.

Then the UE may acquire information broadcast in the cell by receiving aphysical broadcast channel (PBCH) from the base station.

During the initial cell search, the UE may monitor a DL channel state byreceiving a Downlink Reference Signal (DL RS).

After the initial cell search, the UE may acquire more detailed systeminformation by receiving a physical downlink control channel (PDCCH) andreceiving on a physical downlink shared channel (PDSCH) based oninformation of the PDCCH (S12).

Subsequently, to complete connection to the eNB, the UE may perform arandom access procedure with the eNB (S13 to S16). In the random accessprocedure, the UE may transmit a preamble on a physical random accesschannel (PRACH) (S13) and may receive a PDCCH and a random accessresponse (RAR) for the preamble on a PDSCH associated with the PDCCH(S14). The UE may transmit a PUSCH by using scheduling information inthe RAR (S15), and perform a contention resolution procedure includingreception of a PDCCH signal and a PDSCH signal corresponding to thePDCCH signal (S16).

After the above procedure, the UE may receive a PDCCH and/or a PDSCHfrom the BS (S17) and transmit a physical uplink shared channel (PUSCH)and/or a physical uplink control channel (PUCCH) to the BS (S18), in ageneral UL/DL signal transmission procedure.

Control information that the UE transmits to the BS is genericallycalled uplink control information (UCI). The UCI includes a hybridautomatic repeat and request acknowledgement/negative acknowledgement(HARQ-ACK/NACK), a scheduling request (SR), a channel quality indicator(CQI), a precoding matrix index (PMI), a rank indicator (RI), etc.

In general, UCI is transmitted periodically on a PUCCH. However, ifcontrol information and traffic data should be transmittedsimultaneously, the control information and traffic data may betransmitted on a PUSCH. In addition, the UCI may be transmittedaperiodically on the PUSCH, upon receipt of a request/command from anetwork.

1.2. Radio Frame Structures

FIGS. 2A to 3 are diagrams illustrating radio frame structures in an LTEsystem to which embodiments of the present disclosure are applicable.

The LTE system supports frame structure type 1 for frequency divisionduplex (FDD), frame structure type 2 for time division duplex (TDD), andframe structure type 3 for an unlicensed cell (UCell). In the LTEsystem, up to 31 secondary cells (SCells) may be aggregated in additionto a primary cell (PCell). Unless otherwise specified, the followingoperation may be applied independently on a cell basis.

In multi-cell aggregation, different frame structures may be used fordifferent cells. Further, time resources (e.g., a subframe, a slot, anda subslot) within a frame structure may be generically referred to as atime unit (TU).

FIG. 2A illustrates frame structure type 1. Frame type 1 is applicableto both a full Frequency Division Duplex (FDD) system and a half FDDsystem.

A DL radio frame is defined by 10 1-ms subframes. A subframe includes 14or 12 symbols according to a cyclic prefix (CP). In a normal CP case, asubframe includes 14 symbols, and in an extended CP case, a subframeincludes 12 symbols.

Depending on multiple access schemes, a symbol may be an OFDM(A) symbolor an SC-FDM(A) symbol. For example, a symbol may refer to an OFDM(A)symbol on DL and an SC-FDM(A) symbol on UL. An OFDM(A) symbol may bereferred to as a cyclic prefix-OFDMA(A) (CP-OFDM(A)) symbol, and anSC-FMD(A) symbol may be referred to as a discrete Fouriertransform-spread-OFDM(A) (DFT-s-OFDM(A)) symbol.

One subframe may be defined by one or more slots according to asubcarrier spacing (SCS) as follows.

-   -   When SCS=7.5 kHz or 15 kHz, subframe #i is defined by two 0.5-ms        slots, slot #2i and slot #2i+1 (i=0-9).    -   When SCS=1.25 kHz, subframe #i is defined by one 1-ms slot, slot        #2i.    -   When SCS=15 kHz, subframe #i may be defined by six subslots as        illustrated in Table 1.

Table 1 lists exemplary subslot configurations for one subframe (normalCP).

TABLE 1 Subslot number 0 1 2 3 4 5 Slot number 2i 2i + 1 Uplink subslot0, 1, 2 3, 4 5, 6 0, 1 2, 3 4, 5, 6 pattern (Symbol number) Downlinksubslot 0, 1, 2 3, 4 5, 6 0, 1 2, 3 4, 5, 6 pattern 1 (Symbol number)Downlink subslot 0, 1 2, 3, 4 5, 6 0, 1 2, 3 4, 5, 6 pattern 2 (Symbolnumber)

FIG. 2B illustrates frame structure type 2. Frame structure type 2 isapplied to a TDD system. Frame structure type 2 includes two halfframes. A half frame includes 4 (or 5) general subframes and 1 (or 0)special subframe. According to a UL-DL configuration, a general subframeis used for UL or DL. A subframe includes two slots.

Table 2 lists exemplary subframe configurations for a radio frameaccording to UL-DL configurations.

TABLE 2 Uplink- Downlink- downlink to-Uplink configura- Switch pointSubframe number tion periodicity 0 1 2 3 4 5 6 7 8 9 0 5 ms D S U U U DS U U U 1 5 ms D S U U D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms DS U U U D D D D D 4 10 ms D S U U D D D D D D 5 10 ms D S U D D D D D DD 6 5 ms D S U U U D S U U D

In Table 2, D represents a DL subframe, U represents a UL subframe, andS represents a special subframe. A special subframe includes a downlinkpilot time slot (DwPTS), a guard period (GP), and an uplink pilot timeslot (UpPTS). The DwPTS is used for initial cell search,synchronization, or channel estimation at a UE. The UpPTS is used forchannel estimation at an eNB and acquisition of UL transmissionsynchronization at a UE. The GP is a period for cancelling interferenceof a UL caused by the multipath delay of a DL signal between a DL andthe UL.

Table 3 lists exemplary special subframe configurations.

TABLE 3 Normal cyclic prefix in downlink Extended cyclic prefix indownlink Special UpPTS UpPTS subframe Normal cyclic Extended cyclicNormal cyclic Extended cyclic configuration DwPTS prefix in uplinkprefix in uplink DwPTS prefix in uplink prefix in uplink 0  6592 · T_(s)(1 + X) · 2192 · T_(s) (1 + X) · 2560 · T_(s)  7680 · T_(s) (1 + X) ·2192 · T_(s) (1 + X) · 2560 · T_(s) 1 19760 · T_(s) 20480 · T_(s) 221952 · T_(s) 23040 · T_(s) 3 24144 · T_(s) 25600 · T_(s) 4 26336 ·T_(s)  7680 · T_(s) (2 + X) · 2192 · T_(s) (2 + X) · 2560 · T_(s) 5 6592 · T_(s) (2 + X) · 2192 · T_(s) (2 + X) · 2560 · T_(s) 20480 ·T_(s) 6 19760 · T_(s) 23040 · T_(s) 7 21952 · T_(s) 12800 · T_(s) 824144 · T_(s) — — — 9 13168 · T_(s) — — — 10 13168 · T_(s) 13152 · T_(s)12800 · T_(s) — — —

In Table 3, X is configured by higher-layer signaling (e.g., radioresource control (RRC) signaling or the like) or given as 0.

FIG. 3 is a diagram illustrating frame structure type 3.

Frame structure type 3 may be applied to UCell operation. Framestructure type 3 may be applied to, but not limited to, a licensedassisted access (LAA) SCell with a normal CP. A frame is 10 ms induration, including 10 1-ms subframes. Subframe #i is defined by twoconsecutive slots, slot #2i and slot #2i+1. Each subframe in a frame maybe used for a DL or UL transmission or may be empty. A DL transmissionoccupies one or more consecutive subframes, starting from any time in asubframe and ending at a boundary of a subframe or in a DwPTS of Table3. A UL transmission occupies one or more consecutive subframes.

FIG. 4 is a diagram illustrating a slot structure in an LTE system towhich embodiments of the present disclosure are applied.

Referring to FIG. 4, a slot includes a plurality of OFDM symbols in thetime domain by a plurality of resource blocks (RBs) in the frequencydomain. A symbol may refer to a symbol duration. A slot structure may bedescribed by a resource grid including N^(DL/DL) _(RB)N^(RB) _(sc)subcarriers and N^(DL/UL) _(symb) symbols. N^(DL)RB denotes the numberof RBs in a DL slot, and N^(UL)RB denotes the number of RBs in a ULslot. N^(DL) _(RB) and N^(UL) _(RB) are dependent on a DL bandwidth anda UL bandwidth, respectively. N^(DL) _(symb) denotes the number ofsymbols in the DL slot, and N^(UL) _(symb) denotes the number of symbolsin the UL slot. N^(RB) _(sc) denotes the number of subcarriers in oneRB. The number of symbols in a slot may vary depending on SCSs and CPlengths (see Table 1). For example, while one slot includes 7 symbols ina normal CP case, one slot includes 6 symbols in an extended CP case.

An RB is defined as N^(DL/UL) _(symb) (e.g., 7) consecutive symbols inthe time domain by N^(RB) _(sc) (e.g., 12) consecutive subcarriers inthe frequency domain. The RB may be a physical resource block (PRB) or avirtual resource block (VRB), and PRBs may be mapped to VRBs in aone-to-one correspondence. Two RBs each being located in one of the twoslots of a subframe may be referred to as an RB pair. The two RBs of anRB pair may have the same RB number (or RB index). A resource with onesymbol by one subcarrier is referred to as a resource element (RE) ortone. Each RE in the resource grid may be uniquely identified by anindex pair (k, l) in a slot, where k is a frequency-domain index rangingfrom 0 to N^(DL/UL)×N^(RB) _(sc)−1 and l is a time-domain index rangingfrom 0 to N^(DL/DL) _(symb)−1.

FIG. 5 illustrates a DL subframe structure in an LTE system to whichembodiments of the present disclosure are applicable.

Referring to FIG. 5, up to three (or four) OFDM(A) symbols at thebeginning of the first slot of a subframe corresponds to a controlregion. The remaining OFDM(A) symbols correspond to a data region inwhich a PDSCH is allocated, and a basic resource unit of the data regionis an RB. DL control channels include a physical control formatindicator channel (PCFICH), a physical downlink control channel (PDCCH),a physical hybrid-ARQ indicator channel (PHICH), and so on.

The PCFICH is transmitted in the first OFDM symbol of a subframe,carrying information about the number of OFDM symbols (i.e., the size ofa control region) used for transmission of control channels in thesubframe. The PHICH is a response channel for a UL transmission,carrying a hybrid automatic repeat request (HARD) acknowledgement(ACK)/negative acknowledgement (NACK) signal. Control informationdelivered on the PDCCH is called downlink control information (DCI). TheDCI includes UL resource allocation information, DL resource controlinformation, or a UL transmit (TX) power control command for any UEgroup.

FIG. 6 is a diagram illustrating a UL subframe structure in an LTEsystem to which embodiments of the present disclosure are applicable.

Referring to FIG. 6, one subframe 600 includes two 0.5-ms slots 601.Each slot includes a plurality of symbols 602, each corresponding to oneSC-FDMA symbol. An RB 603 is a resource allocation unit corresponding to12 subcarriers in the frequency domain by one slot in the time domain.

A UL subframe is divided largely into a data region 604 and a controlregion 605. The data region is communication resources used for each UEto transmit data such as voice, packets, and so on, including a physicaluplink shared channel (PUSCH). The control region is communicationresources used for each UE to transmit an ACK/NACK for a DL channelquality report or a DL signal, a UL scheduling request, and so on,including a physical uplink control channel (PUCCH).

A sounding reference signal (SRS) is transmitted in the last SC-FDMAsymbol of a subframe in the time domain.

FIG. 7 is a diagram illustrating a radio frame structure in an NR systemto which embodiments of the present disclosure are applicable.

In the NR system, UL and DL transmissions are based on a frame asillustrated in FIG. 7. One radio frame is 10 ms in duration, defined astwo 5-ms half-frames. One half-frame is defined as five 1-ms subframes.One subframe is divided into one or more slots, and the number of slotsin a subframe depends on an SCS. Each slot includes 12 or 14 OFDM(A)symbols according to a CP. Each slot includes 14 symbols in a normal CPcase, and 12 symbols in an extended CP case. Herein, a symbol mayinclude an OFDM symbol (or a CP-OFDM symbol) and an SC-FDMA symbol (or aDFT-s-OFDM symbol).

Table 4 lists the number of symbols per slot, the number of slots perframe, and the number of slots per subframe in the normal CP case, andTable 5 lists the number of symbols per slot, the number of slots perframe, and the number of slots per subframe in the extended CP case.

TABLE 4 μ N_(symb) ^(slot) N_(slot) ^(frame, μ) N_(slot) ^(subframe, μ)0 14 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16 5 14 320 32

TABLE 5 μ N_(symb) ^(slot) N_(slot) ^(frame, μ) N_(slot) ^(subframe, μ)2 12 40 4

In the above tables, N^(slot) _(symb) denotes the number of symbols in aslot, N^(frame,μ) _(slot) denotes the number of slots in a frame, andN^(subframe,μ) _(slot) denotes the number of slots in a subframe.

In the NR system to which the present disclosure is applicable,different OFDM(A) numerologies (e.g., SCSs, CP length, and so on) may beconfigured for a plurality of cells aggregated for a UE. Therefore, the(absolute) duration of a time resource (e.g., an SF, slot, or TTI) (forthe convenience of description, generically referred to as a time unit(TU)) including the same number of symbols may be different between theaggregated cells.

FIG. 8 is a diagram illustrating a slot structure in an NR system towhich embodiments of the present disclosure are applicable.

One slot includes a plurality of symbols in the time domain. Forexample, one slot includes 7 symbols in a normal CP case and 6 symbolsin an extended CP case.

A carrier includes a plurality of subcarriers in the frequency domain.An RB is defined as a plurality of (e.g., 12) consecutive subcarriers inthe frequency domain.

A bandwidth part (BWP) is defined as a plurality of consecutive (P)RBsin the frequency domain and may correspond to one numerology (e.g., SCS,CP length, and so on).

A carrier may include up to N (e.g., 5) BWPs. Data communication may beconducted in an active BWP, and only one BWP may be activated for oneUE. In a resource grid, each element is referred to as an RE, to whichone complex symbol may be mapped.

FIG. 9 is a diagram illustrating a self-contained slot structures in anNR system to which embodiments of the present disclosure are applicable.

In FIG. 9, the hatched area (e.g., symbol index=0) indicates a DLcontrol region, and the black area (e.g., symbol index=13) indicates aUL control region. The remaining area (e.g., symbol index=1 to 12) maybe used for DL or UL data transmission.

Based on this structure, an eNB and a UE may sequentially perform DLtransmission and UL transmission in one slot. That is, the eNB and UEmay transmit and receive not only DL data but also a UL ACK/NACK for theDL data in one slot. Consequently, this structure may reduce a timerequired until data retransmission when a data transmission erroroccurs, thereby minimizing the latency of a final data transmission.

In this self-contained slot structure, a predetermined length of timegap is required to allow the eNB and UE to switch from transmission modeto reception mode and vice versa. To this end, in the self-containedslot structure, some OFDM symbols at the time of switching from DL to ULmay be configured as a guard period (GP).

Although it has been described above that the self-contained slotstructure includes both DL and UL control regions, these control regionsmay be selectively included in the self-contained slot structure. Inother words, the self-contained slot structure according to the presentdisclosure may include either the DL control region or the UL controlregion as well as both the DL and UL control regions as illustrated inFIG. 9.

Further, the order of regions in one slot may vary in some embodiments.For example, one slot may be configured in the following order: DLcontrol region, DL data region, UL control region, and UL data region,or UL control region, UL data region, DL control region, and DL dataregion.

A PDCCH may be transmitted in the DL control region, and a PDSCH may betransmitted in the DL data region. A PUCCH may be transmitted in the ULcontrol region, and a PUSCH may be transmitted in the UL data region.

The PDCCH may deliver downlink control information (DCI), for example,DL data scheduling information, UL data scheduling information, and soon. The PUCCH may deliver uplink control information (UCI), for example,an ACK/NACK for DL data, channel state information (CSI), a schedulingrequest (SR), and so on.

The PDSCH carries DL data (e.g., DL-shared channel transport block(DL-SCH TB)) and uses a modulation scheme such as quadrature phase shiftkeying (QPSK), 16-ary quadrature amplitude modulation (16QAM), 64QAM, or256QAM. A TB is encoded into a codeword. The PDSCH may deliver up to twocodewords. Scrambling and modulation mapping are performed on a codewordbasis, and modulation symbols generated from each codeword are mapped toone or more layers (layer mapping). Each layer is mapped to resourcestogether with a demodulation reference signal (DMRS or DM-RS), createdas an OFDM symbol signal, and then transmitted through a correspondingantenna port.

The PDCCH carries DCI and uses QPSK as a modulation scheme. One PDCCHincludes 1, 2, 4, 8, or 16 control channel elements (CCEs) according toan aggregation level (AL). One CCE includes 6 resource element groups(REGs). One REG is defined as one OFDM symbol by one (P)RB.

FIG. 10 is a diagram illustrating the structure of one REG in an NRsystem to which embodiments of the present disclosure are applicable.

In FIG. 10, D denotes an RE to which DCI is mapped, and R denotes an REto which a DMRS is mapped. The DMRS is mapped to REs #1, #5, and #9along the frequency axis in one symbol.

The PDCCH is transmitted in a control resource set (CORESET). A CORESETis defined as a set of REGs having a given numerology (e.g., SCS, CPlength, and so on). A plurality of CORESETs for one UE may overlap witheach other in the time/frequency domain. A CORESET may be configured bysystem information (e.g., a master information block (MIB)) or byUE-specific higher layer (RRC) signaling. Specifically, the number ofRBs and the number of symbols (up to 3 symbols) included in a CORESETmay be configured by higher-layer signaling.

The PUSCH carries UL data (e.g., UL-shared channel transport block(UL-SCH TB)) and/or UCI and is transmitted based on a CP-OFDM waveformor a DFT-s-OFDM waveform. When the PUSCH is transmitted in theDFT-s-OFDM waveform, the UE transmits the PUSCH by applying transformprecoding. For example, when transform precoding is impossible (e.g.,disabled), the UE may transmit the PUSCH in the CP-OFDM waveform, whilewhen transform precoding is possible (e.g., enabled), the UE maytransmit the PUSCH in the CP-OFDM or DFT-s-OFDM waveform. PUSCHtransmission may be dynamically scheduled by a UL grant in DCI, orsemi-statically scheduled by higher-layer (e.g., RRC) signaling (and/orlayer 1 (L1) signaling such as a PDCCH) (configured grant). Bothcodebook based PUSCH transmission and non-codebook based PUSCHtransmission may be allowed.

The PUCCH carries UCI, an HARQ-ACK, and/or an SR. Depending on thetransmission duration of the PUCCH, the PUCCH is classified into a shortPUCCH and a long PUCCH. Table 6 lists exemplary PUCCH formats.

TABLE 6 Length in OFDM PUCCH symbols Number format N_(symb) ^(PUCCH) ofbits Usage Etc 0 1-2  ≤2 HARQ, SR Sequence selection 1 1-14 ≤2 HARQ,[SR] Sequence moclulation 2 1-2  >2 HARQ, CSI, [SR] CP-OFDM 3 4-14 >2HARQ, CSI, [SR] DFT-s-OFDM (no UE multiplexing) 4 4-14 >2 HARQ, CSI,[SR] DFT-s-OFDM (Pre DFT OCC)

PUCCH format 0 carries UCI of up to 2 bits and is mapped in asequence-based manner, for transmission. Specifically, the UE transmitsspecific UCI to the eNB by transmitting one of a plurality of sequenceson a PUCCH of PUCCH format 0. Only when the UE transmits a positive SR,the UE transmits the PUCCH of PUCCH format 0 in a PUCCH resource for acorresponding SR configuration.

PUCCH format 1 carries UCI of up to 2 bits and modulation symbols arespread with an orthogonal cover code (OCC) (which is configureddifferently depending on whether frequency hopping is performed) in thetime domain. The DMRS is transmitted in a symbol in which a modulationsymbol is not transmitted (i.e., transmitted by time divisionmultiplexing (TDM)).

PUCCH format 2 carries UCI of more than 2 bits and modulation symbolsare transmitted by frequency division multiplexing (FDM) with the DMRS.The DMRS is located in symbols #1, #4, #7, and #10 of a given RB with adensity of ⅓. A pseudo noise (PN) sequence is used for a DMRS sequence.For 2-symbol PUCCH format 2, frequency hopping may be activated.

PUCCH format 3 does not support UE multiplexing in the same PRBs andcarries UCI of more than 2 bits. In other words, PUCCH resources ofPUCCH format 3 include no OCC. Modulation symbols are transmitted by TDMwith the DMRS.

PUCCH format 4 supports multiplexing of up to 4 UEs in the same PRBs andcarries UCI of more than 2 bits. In other words, PUCCH resources ofPUCCH format 3 includes an OCC. Modulation symbols are transmitted inTDM with the DMRS.

1.3. Analog Beamforming

In a millimeter wave (mmW) system, since a wavelength is short, aplurality of antenna elements can be installed in the same area. Thatis, considering that the wavelength at 30 GHz band is 1 cm, a total of100 antenna elements can be installed in a 5*5 cm panel at intervals of0.5 lambda (wavelength) in the case of a 2-dimensional array. Therefore,in the mmW system, it is possible to improve the coverage or throughputby increasing the beamforming (BF) gain using multiple antenna elements.

In this case, each antenna element can include a transceiver unit (TXRU)to enable adjustment of transmit power and phase per antenna element. Bydoing so, each antenna element can perform independent beamforming perfrequency resource.

However, installing TXRUs in all of the about 100 antenna elements isless feasible in terms of cost. Therefore, a method of mapping aplurality of antenna elements to one TXRU and adjusting the direction ofa beam using an analog phase shifter has been considered. However, thismethod is disadvantageous in that frequency selective beamforming isimpossible because only one beam direction is generated over the fullband.

To solve this problem, as an intermediate form of digital BF and analogBF, hybrid BF with B TXRUs that are fewer than Q antenna elements can beconsidered. In the case of the hybrid BF, the number of beam directionsthat can be transmitted at the same time is limited to B or less, whichdepends on how B TXRUs and Q antenna elements are connected.

FIGS. 11 and 12 are diagrams illustrating representative methods forconnecting TXRUs to antenna elements. Here, the TXRU virtualizationmodel represents the relationship between TXRU output signals andantenna element output signals.

FIG. 11 shows a method for connecting TXRUs to sub-arrays. In FIG. 11,one antenna element is connected to one TXRU.

Meanwhile, FIG. 12 shows a method for connecting all TXRUs to allantenna elements. In FIG. 12, all antenna elements are connected to allTXRUs. In this case, separate addition units are required to connect allantenna elements to all TXRUs as shown in FIG. 12.

In FIGS. 11 and 12, W indicates a phase vector weighted by an analogphase shifter. That is, W is a major parameter determining the directionof the analog beamforming. In this case, the mapping relationshipbetween CSI-RS antenna ports and TXRUs may be 1:1 or 1-to-many.

The configuration shown in FIG. 11 has a disadvantage in that it isdifficult to achieve beamforming focusing but has an advantage in thatall antennas can be configured at low cost.

On the contrary, the configuration shown in FIG. 12 is advantageous inthat beamforming focusing can be easily achieved. However, since allantenna elements are connected to the TXRU, it has a disadvantage ofhigh cost.

When a plurality of antennas is used in the NR system to which thepresent disclosure is applicable, a hybrid beamforming (BF) scheme inwhich digital BF and analog BF are combined may be applied. In thiscase, analog BF (or radio frequency (RF) BF) means an operation ofperforming precoding (or combining) at an RF stage. In hybrid BF, eachof a baseband stage and the RF stage perform precoding (or combining)and, therefore, performance approximating to digital BF can be achievedwhile reducing the number of RF chains and the number of adigital-to-analog (D/A) (or analog-to-digital (A/D) converters.

For convenience of description, a hybrid BF structure may be representedby N transceiver units (TXRUs) and M physical antennas. In this case,digital BF for L data layers to be transmitted by a transmission end maybe represented by an N-by-L matrix. N converted digital signals obtainedthereafter are converted into analog signals via the TXRUs and thensubjected to analog BF, which is represented by an M-by-N matrix.

FIG. 13 is a diagram schematically illustrating an exemplary hybrid BFstructure from the perspective of TXRUs and physical antennas accordingto the present disclosure. In FIG. 13, the number of digital beams is Land the number analog beams is N.

Additionally, in the NR system to which the present disclosure isapplicable, an BS designs analog BF to be changed in units of symbols toprovide more efficient BF support to a UE located in a specific area.Furthermore, as illustrated in FIG. 13, when N specific TXRUs and M RFantennas are defined as one antenna panel, the NR system according tothe present disclosure considers introducing a plurality of antennapanels to which independent hybrid BF is applicable.

In the case in which the BS utilizes a plurality of analog beams asdescribed above, the analog beams advantageous for signal reception maydiffer according to a UE. Therefore, in the NR system to which thepresent disclosure is applicable, a beam sweeping operation is beingconsidered in which the BS transmits signals (at least synchronizationsignals, system information, paging, and the like) by applying differentanalog beams in a specific subframe (SF) or slot on a symbol-by-symbolbasis so that all UEs may have reception opportunities.

FIG. 14 is a diagram schematically illustrating an exemplary beamsweeping operation for a synchronization signal and system informationin a DL transmission procedure according to the present disclosure.

In FIG. 14 below, a physical resource (or physical channel) on which thesystem information of the NR system to which the present disclosure isapplicable is transmitted in a broadcasting manner is referred to as anxPBCH. Here, analog beams belonging to different antenna panels withinone symbol may be simultaneously transmitted.

As illustrated in FIG. 14, in order to measure a channel for each analogbeam in the NR system to which the present disclosure is applicable,introducing a beam RS (BRS), which is a reference signal (RS)transmitted by applying a single analog beam (corresponding to aspecific antenna panel), is being discussed. The BRS may be defined fora plurality of antenna ports and each antenna port of the BRS maycorrespond to a single analog beam. In this case, unlike the BRS, asynchronization signal or the xPBCH may be transmitted by applying allanalog beams in an analog beam group such that any UE may receive thesignal well.

1.4. Synchronization Signal Block (SSB) or SS/PBCH Block

In the NR system to which the present disclosure is applicable, aprimary synchronization signal (PSS), a secondary synchronization signal(SSS), and/or a physical broadcast signal (PBCH) may be transmitted inone SS block or SS PBCH block (hereinafter, referred to as an SSB orSS/PBCH block). Multiplexing other signals may not be precluded withinthe SSB.

The SS/PBCH block may be transmitted in a band other than the center ofa system band. Particularly, when the BS supports broadband operation,the BS may transmit multiple SS/PBCH blocks.

FIG. 15 is a schematic diagram illustrating an SS/PBCH block applicableto the present disclosure.

As illustrated in FIG. 15, the SS/PBCH block applicable to the presentdisclosure may include 20 RBs in four consecutive OFDM symbols. Further,the SS/PBCH block may include a PSS, an SSS, and a PBCH, and the UE mayperform cell search, system information acquisition, beam alignment forinitial access, DL measurement, and so on based on the SS/PBCH block.

Each of the PSS and the SSS includes one OFDM symbol by 127 subcarriers,and the PBCH includes three OFDM symbols by 576 subcarriers. Polarcoding and QPSK are applied to the PBCH. The PBCH includes data REs andDMRS REs in every OFDM symbol. There are three DMRS REs per RB, withthree data REs between every two adjacent DMRS REs.

Further, the SS/PBCH block may be transmitted even in a frequency bandother than the center frequency of a frequency band used by the network.

For this purpose, a synchronization raster being candidate frequencypositions at which the UE should detect the SS/PBCH block is defined inthe NR system to which the present disclosure is applicable. Thesynchronization raster may be distinguished from a channel raster.

In the absence of explicit signaling of the position of the SS/PBCHblock, the synchronization raster may indicate available frequencypositions for the SS/PBCH block, at which the UE may acquire systeminformation.

The synchronization raster may be determined based on a globalsynchronization channel number (GSCN). The GSCN may be transmitted byRRC signaling (e.g., an MIB, a system information block (SIB), remainingminimum system information (RMSI), other system information (OSI), orthe like).

The synchronization raster is defined to be longer along the frequencyaxis than the channel raster and characterized by a smaller number ofblind detections than the channel raster, in consideration of thecomplexity of initial synchronization and a detection speed.

FIG. 16 is a schematic diagram illustrating an SS/PBCH blocktransmission structure applicable to the present disclosure.

In the NR system to which the present disclosure is applicable, the BSmay transmit an SS/PBCH block up to 64 times for 5 ms. The multipleSS/PBCH blocks may be transmitted on different beams, and the UE maydetect the SS/PBCH block on the assumption that the SS/PBCH block istransmitted on a specific one beam every 20 ms.

As the frequency band is higher, the BS may set a larger maximum numberof beams available for SS/PBCH block transmission within 5 ms. Forexample, the BS may transmit the SS/PBCH block by using up to 4different beams at or below 3 GHz, up to 8 different beams at 3 to 6GHz, and up to 64 different beams at or above 6 GHz, for 5 ms.

1.5. Synchronization Procedure

The UE may acquire synchronization by receiving the above-describedSS/PBCH block from the BS. The synchronization procedure largelyincludes cell ID detection and timing detection. The cell ID detectionmay include PSS-based cell ID detection and SSS-based cell ID detection.The timing detection may include PBCH DMRS-based timing detection andPBCH contents-based (e.g., MIB-based) timing detection.

First, the UE may acquire timing synchronization and the physical cellID of a detected cell by detecting a PSS and an SSS. More specifically,the UE may acquire the symbol timing of the SS block and detect a cellID within a cell ID group, by PSS detection. Subsequently, the UEdetects the cell ID group by SSS detection.

Further, the UE may detect the time index (e.g., slot boundary) of theSS block by the DMRS of the PBCH. The UE may then acquire half-frameboundary information and system frame number (SFN) information from anMIB included in the PBCH.

The PBCH may indicate that a related (or corresponding) RMSI PDCCH/PDSCHis transmitted in the same band as or a different band from that of theSS/PBCH block. Accordingly, the UE may then receive RMSI (e.g., systeminformation other than the MIB) in a frequency band indicated by thePBCH or a frequency band carrying the PBCH, after decoding of the PBCH.

In relation to the operation, the UE may acquire system information.

The MIB includes information/parameters required for monitoring a PDCCHthat schedules a PDSCH carrying SystemInformationBlock1 (SIB1), and istransmitted to the UE on the PBCH in the SS/PBCH block by the gNB.

The UE may check whether there is a CORESET for a Type0-PDCCH commonsearch space, based on the MIB. The Type0-PDCCH common search space is akind of PDCCH search space and used to transmit a PDCCH that schedulesan SI message.

In the presence of a Type0-PDCCH common search space, the UE maydetermine (i) a plurality of contiguous RBs included in the CORESET andone or more consecutive symbols and (ii) a PDCCH occasion (e.g., atime-domain position for PDCCH reception), based on information (e.g.,pdcch-ConfigSIB1) included in the MIB.

In the absence of a Type0-PDCCH common search space, pdcch-ConfigSIB1provides information about a frequency position at which the SSB/SIB1exists and a frequency range in which the SSB/SIB1 does not exist.

SIB1 includes information about the availability and scheduling of theother SIBs (hereinafter, referred to as SIBx where x is 2 or a largerinteger). For example, SIB1 may indicate whether SIBx is periodicallybroadcast or provided in an on-demand manner (or upon request of theUE). When SIBx is provided in the on-demand manner, SIB1 may includeinformation required for an SI request of the UE. SIB1 is transmitted ona PDSCH. A PDCCH that schedules SIB1 is transmitted in a Type0-PDCCHcommon search space, and SIB1 is transmitted on a PDSCH indicated by thePDCCH.

1.6. Quasi Co-Located or Quasi Co-Location (QCL)

In the present disclosure, QCL may mean one of the following.

(1) If two antenna ports are “quasi co-located (QCL)”, the UE may assumethat large-scale properties of a signal received from a first antennaport may be inferred from a signal received from the other antenna port.The “large-scale properties” may include one or more of the following.

-   -   Delay spread    -   Doppler spread    -   Frequency shift    -   Average received power    -   Received Timing

(2) If two antenna ports are “quasi co-located (QCL)”, the UE may assumethat large-scale properties of a channel over which a symbol on oneantenna port is conveyed may be inferred from a channel over which asymbol on the other antenna port is conveyed). The “large-scaleproperties” may include one or more of the following.

-   -   Delay spread    -   Doppler spread    -   Doppler shift    -   Average gain    -   Average delay    -   Average angle (AA): When it is said that QCL is guaranteed        between antenna ports in terms of AA, this may imply that when a        signal is to be received from other antenna port(s) based on an        AA estimated from specific antenna port(s), the same or similar        reception beam direction (and/or reception beam width/sweeping        degree) may be set and the reception is processed accordingly        (in other words, that when operated in this manner, reception        performance at or above a certain level is guaranteed).    -   Angular spread (AS): When it is said that QCL is guaranteed        between antenna ports in terms of AS, this may imply that an AS        estimated from one antenna port may be derived/estimated/applied        from an AS estimated from another antenna port.    -   Power Angle(-of-Arrival) Profile (PAP): When it is said that QCL        is guaranteed between antenna ports in terms of PAP, this may        imply that a PAP estimated from one antenna port may be        derived/estimated/applied from a PAP estimated from another        antenna port (or the PAPs may be treated as similar or        identical).

In the present disclosure, both of the concepts defined in (1) and (2)described above may be applied to QCL. Alternatively, the QCL conceptsmay be modified such that it may be assumed that signals are transmittedfrom a co-location, for signal transmission from antenna ports for whichthe QCL assumption is established (e.g., the UE may assume that theantenna ports are transmitted from the same transmission point).

In the present disclosure, partial QCL between two antenna ports maymean that at least one of the foregoing QCL parameters for one antennaport is assumed/applied/used as the same as for the other antenna port(when an associated operation is applied, performance at or above acertain level is guaranteed).

1.7. Bandwidth Part (BWP)

In the NR system to which the present disclosure is applicable, afrequency resource of up to 400 MHz may be allocated/supported for eachCC. When a UE operating in such a wideband CC always operates with aradio frequency (RF) module for the entire CCs turned on, batteryconsumption of the UE may increase.

Alternatively, considering various use cases (e.g., enhanced mobilebroadband (eMBB), ultra-reliable and low latency communication (URLLC),and massive machine type communication (mMTC), and so on) operatingwithin a single wideband CC, a different numerology (e.g., SCS) may besupported for each frequency band within the CC.

Alternatively, the maximum bandwidth capability may be different foreach UE.

In consideration of the above situation, the BS may indicate/configurethe UE to operate only in a partial bandwidth instead of the entirebandwidth of the wideband CC. The partial bandwidth may be defined as aBWP.

A BWP may include consecutive RBs on the frequency axis, and one BWP maycorrespond to one numerology (e.g., SCS, CP length, slot/mini-slotduration, and so on).

The BS may configure a plurality of BWPs in one CC configured for theUE. For example, the BS may configure a BWP occupying a relatively smallfrequency region in a PDCCH monitoring slot, and schedule a PDSCHindicated by the PDCCH (or a PDSCH scheduled by the PDCCH) in a largerBWP. Alternatively, when UEs are concentrated on a specific BWP, the BSmay configure another BWP for some of the UEs, for load balancing.Alternatively, the BS may exclude some spectrum of the entire bandwidthand configure both of the BWPs in the same slot in consideration offrequency-domain inter-cell interference cancellation betweenneighboring cells.

The BS may configure at least one DL/UL BWP for the UE associated withthe wideband CC and activate at least one DL/UL BWP among the configuredDL/UL BWP(s) at a specific time (through L1 signaling (e.g., DCI), MACor RRC signaling, etc.). The activated DL/UL BWP may be called an activeDL/UL BWP. The UE may fail to receive DL/UL BWP configurations from theBS during an initial access procedure or before setting up an RRCconnection. A DL/UL BWP assumed by such a UE is defined as an initialactive DL/UL BWP.

2. Unlicensed Band System

FIGS. 17A and 17B illustrate a wireless communication system supportingan unlicensed band applicable to the present disclosure.

Herein, a cell operating in a licensed band (L-band) is defined as anL-cell, and a carrier in the L-cell is defined as a (DL/UL) LCC. A celloperating in an unlicensed band (U-band) is defined as a U-cell, and acarrier in the U-cell is defined as a (DL/UL) UCC. Thecarrier/carrier-frequency of a cell may refer to the operating frequency(e.g., center frequency) of the cell. A cell/carrier (e.g., CC) iscommonly called a cell.

When a BS and a UE transmit and receive signals on an LCC and a UCCwhere carrier aggregation is applied as shown in FIG. 17A, the LCC andthe UCC may be set to a primary CC (PCC) and a secondary CC (SCC),respectively.

The BS and UE may transmit and receive signals on one UCC or on aplurality of UCCs where the carrier aggregation is applied as shown inFIG. 17B. In other words, the BS and UE may transmit and receive signalson UCC(s) with no LCC.

Signal transmission and reception operations in U-bands, which will bedescribed later in the present disclosure, may be applied to all of theaforementioned deployment scenarios (unless specified otherwise).

2.1. Radio Frame Structure for Unlicensed Band

For operation in U-bands, LTE frame structure type 3 (see FIG. 3) or theNR frame structure (see FIG. 7) may be used. The configuration of OFDMsymbols reserved for UL/DL signal transmission in a frame structure forU-bands may be determined by a BS. In this case, the OFDM symbol may bereplaced with an SC-FDM(A) symbol.

To transmit a DL signal in a U-band, the BS may inform a UE of theconfiguration of OFDM symbols used in subframe #n through signaling.Herein, a subframe may be replaced with a slot or a time unit (TU).

Specifically, in the LTE system supporting U-bands, the UE may assume(or recognize) the configuration of occupied OFDM symbols in subframe #nbased on a specific filed in DCI (e.g., Subframe configuration for LAA′field, etc.), which is received in subframe #n−1 or subframe #n from theBS.

Table 7 shows how the Subframe configuration for LAA field indicates theconfiguration of OFDM symbols used to transmit DL physical channelsand/or physical signals in the current or next subframe.

TABLE 7 Value of Configuration of occupied OFDM ‘Subframe configurationfor LAA’ symbols field in current subframe (current subframe, nextsubframe) 0000 (—, 14) 0001 (—, 12) 0010 (—, 11) 0011 (—, 10) 0100 (—,9)  0101 (—, 6)  0110 (—, 3)  0111 (14, *)  1000 (12, —) 1001 (11, —)1010 (10, —) 1011  (9, —) 1100  (6, —) 1101  (3, —) 1110 reserved 1111reserved NOTE: (—, Y) means UE may assume the first Y symbols areoccupied in next subframe and other symbols in the next subframe are notoccupied. (X, —) means UE may assume the first X symbols are occupied incurrent subframe and other symbols in the current subframe are notoccupied. (X, *) means UE may assume the first X symbols are occupied incurrent subframe, and at least the first OFDM symbol of the nextsubframe is not occupied.

To transmit a UL signal in a U-band, the BS may provide information on aUL transmission interval to the UE through signaling.

Specifically, in the LTE system supporting U-bands, the UE may obtain‘UL duration’ and ‘UL offset’ information for subframe #n from the ‘ULduration and offset’ field in detected DCI.

Table 8 shows how the UL duration and offset field indicates theconfigurations of a UL offset and a UL duration.

TABLE 8 Value of UL offset, l UL duration, d ‘UL duration and offset’field (in subframes) (in subframes) 00000 Not configured Not configured00001 1 1 00010 1 2 00011 1 3 00100 1 4 00101 1 5 00110 1 6 00111 2 101000 2 2 01001 2 3 01010 2 4 01011 o 5 01100 2 6 01101 3 1 01110 3 201111 3 3 10000 3 4 10001 3 5 10010 3 6 10011 4 1 10100 4 2 10101 4 310110 4 4 10111 4 5 11000 4 6 11001 6 1 11010 6 2 11011 6 3 11100 6 411101 6 5 11110 6 6 11111 reserved reserved

For example, when the UL duration and offset field configures (orindicates) a UL offset 1 and UL a duration d for subframe #n, the UE maynot need to receive DL physical channels and/or physical signals insubframe #n+l+i (where i=0, 1, . . . , d−1).

2.2. Downlink Channel Access Procedures

To transmit a DL signal in a U-band, a BS may perform a channel accessprocedure (CAP) for the U-band as follows. In the following description,it is assumed that a BS is basically configured with a PCellcorresponding to an L-band and at least one SCell, each corresponding toa U-band. The U-band may be referred to as a licensed assisted access(LAA) SCell. Hereinafter, a description will be given of DL CAPoperation applicable to the present disclosure. In this case, the DL CAPoperation may be equally applied when the BS is configured only withU-bands.

2.2.1. Channel Access Procedure for Transmission(s) IncludingPDSCH/PDCCH/EPDCCH

A BS may transmit a transmission including a PDSCH/PDCCH/EPDCCH on acarrier on which LAA SCell(s) transmission(s) are performed aftersensing whether the channel is idle during the slot durations of a deferduration T_(d) and after a counter N becomes zero in step 4. In thiscase, the counter N is adjusted by sensing the channel for an additionalslot duration according to the following steps.

1) N is set to N_(init) (N=N_(init)), where N_(init) is a random numberuniformly distributed between 0 and CW_(p). Then, step 4 proceeds.

2) If N>0 and the BS chooses to decrease the counter, N is set to N−1(N=N−1).

3) The channel for the additional slot duration is sensed. If theadditional slot duration is idle, step 4 proceeds. Otherwise, step 5proceeds.

4) If N=0, the corresponding process is stopped. Otherwise, step 2proceeds.

5) The channel is sensed until either a busy slot is detected within anadditional defer duration T_(d) or all the slots of the additional deferduration T_(d) are detected to be idle.

6) If the channel is sensed to be idle during all the slot durations ofthe additional defer duration T_(d), step 4 proceeds. Otherwise, step 5proceeds.

The CAP for the transmission including the PDSCH/PDCCH/EPDCCH performedby the BS may be summarized as follows.

FIG. 18 is a diagram for explaining a CAP for U-band transmissionapplicable to the present disclosure.

For DL transmission, a transmission node (e.g., BS) may initiate a CAPto operate in LAA SCell(s), each corresponding to a U-band cell (S1810).

The BS may randomly select a backoff counter N within a contentionwindow (CW) according to step 1. In this case, N is set to an initialvalue, N_(init) (S1820). N_(init) may have a random value between 0 andCW_(p).

If the backoff counter value (N) is 0 (YES in S1830), the BS terminatesthe CAP according to step 4 (S1832). Then, the BS may transmit atransmission (Tx) burst including the PDSCH/PDCCH/EPDCCH (S1834). If thebackoff counter value is non-zero (NO in S1830), the BS decreases thebackoff counter value by 1 according to step 2 (S1840).

The BS checks whether the channel of the LAA SCell(s) is idle (S1850).If the channel is idle (YES in S1850), the BS checks whether the backoffcounter value is 0 (S1830).

If the channel is not idle in S1850, that is, if the channel is busy (NOin S1850), the BS checks whether the corresponding channel is idleduring the defer duration T_(d) (longer than or equal to 25 usec), whichis longer than the slot duration (e.g., 9 usec), according to step 5(S1860). If the channel is idle (YES in S1870), the BS may resume theCAP.

For example, when the backoff counter value N is 10, if the channel isdetermined to be busy after the backoff counter value is reduced to 5,the BS determines whether the channel is idle by sensing the channelduring the defer duration. In this case, if the channel is idle duringthe defer duration, the BS performs the CAP again starting at thebackoff counter value of 5 (or at 4 by decreasing the backoff countervalue by 1), instead of configuring the backoff counter value N_(init).

On the other hand, if the channel is busy during the defer duration (NOin S1870), the BS performs steps S1860 again to check whether thechannel is idle during a new defer duration.

When the BS does not transmit the transmission including thePDSCH/PDCCH/EPDCCH on the carrier on which the LAA SCell(s)transmission(s) are performed after step 4 in the above procedure, theBS may transmit the transmission including the PDSCH/PDCCH/EPDCCH on thecarrier if the following conditions are satisfied:

When the BS is ready to transmit the PDSCH/PDCCH/EPDCCH and the channelis sensed to be idle at least in a slot duration T_(sl); and when thechannel is sensed to be idle during all the slot durations of the deferduration T_(d) immediately before the transmission.

If the channel is sensed not to be idle during the slot duration T_(sl)when the BS senses the channel after being ready to transmit or if thechannel is sensed not to be idle during any one of the slot durations ofthe defer duration T_(d) immediately before the intended transmission,the BS proceeds to step 1 after sensing the channel to be idle duringthe slot durations of the defer duration T_(d).

The defer duration T_(d) includes a duration T_(f)=(=16 us) immediatelyfollowed by m_(p) consecutive slot durations. Here, each slot duration(T_(sl)) is 9 us long, and T_(f) includes an idle slot duration T_(sl)at the start thereof.

When the BS senses the channel during the slot duration T_(sl), if thepower detected by the BS for at least 4 us within the slot duration isless than an energy detection threshold X_(Thresh), the slot durationT_(sl) is considered to be idle. Otherwise, the slot duration T_(sl) isconsidered to be busy.

CW_(min,p)≤CW_(p)≤CW_(max,p) represents the CW. The adjustment of CW_(p)will be described in detail in clause 2.2.3.

CW_(min,p) and CW_(max,p) are selected before step 1 of the aboveprocedure.

m_(p), CW_(min,p) and CW_(p) are determined based on channel accesspriority classes associated with transmissions at the BS (see Table 9below).

The adjustment of X_(Thresh) will be described in clause 2.2.4.

TABLE 9 Channel Access Priority allowed CW_(p) Class (p) m_(p)CW_(min, p) CW_(max, p) T_(mcot, p) sizes 1 1 3 7 2 ms {3, 7}  2 1 7 153 ms {7, 15} 3 3 15 63 8 or 10 ms {15, 31, 63} 4 7 15 1023 8 or 10 ms{15, 31, 63, 127, 255, 511, 1023}

When N>0 in the above procedure, if the BS transmits a discovery signalnot including the PDSCH/PDCCH/EPDCCH, the BS may not decrease thecounter N during slot duration(s) overlapping with the discovery signaltransmission.

The BS may not continuously perform transmission on the carrier on whichthe LAA SCell(s) transmission(s) are performed for a period exceedingT_(mcot,p) in Table 9 above.

For p=3 and p=4 in Table 9 above, if the absence of any othertechnologies sharing the carrier can be guaranteed on a long term basis(e.g. by level of regulation), T_(mcot,p) is set to 10 ms. Otherwise,T_(mcot,p) is set to 8 ms.

2.2.2. Channel Access Procedure for Transmissions Including DiscoverySignal Transmission(s) and not Including PDSCH

When a BS has a transmission duration less than or equal to 1 ms, the BSmay performs transmission including a discovery signal but not includinga PDSCH on a carrier on which LAA SCell(s) transmission(s) are performedimmediately after sensing that the channel is idle at least for asensing interval T_(drs) of 25 us. T_(drs) includes a duration T_(f)(=16 us) immediately followed by one slot duration T_(sl) of 9 us. T_(f)includes an idle slot duration T_(sl) at the start thereof. When thechannel is sensed to be idle during the slot durations of T_(drs), thechannel is considered to be idle for T_(drs).

2.2.3. Contention Window Adjustment Procedure

If a BS transmits transmissions including PDSCHs that are associatedwith the channel access priority class p on a carrier, the BS maintainsthe CW value CW_(p) and adjusts CW_(p) for the transmissions before step1 of the procedure described in clause 2.2.1 (i.e., before performingthe CAP) according to the following steps.

1> For every priority class p∈{1, 2, 3, 4}, CW_(p) is set to CW_(min,p).

2> If at least Z=80% of HARQ-ACK values corresponding to PDSCHtransmission(s) in reference subframe k are determined as NACK, CW_(p)for every priority class p∈{1, 2, 3, 4} increases to a next higherallowed value, and step 2 remains. Otherwise, step 1 proceeds.

In other words, the probability that the HARQ-ACK values correspondingto the PDSCH transmission(s) in reference subframe k are determined asNACK is at least 80%, the BS increases the CW values configured for theindividual priority classes to next higher allowed values, respectively.Alternatively, the BS may maintain the CW value configured for eachpriority class as an initial value.

In this case, reference subframe k is the starting subframe of the mostrecent transmission on the carrier made by the BS, for which at leastsome HARQ-ACK feedback is expected to be available.

The BS may adjust the value of CW_(p) for every priority class p∈{1, 2,3, 4} based on given reference subframe k only once.

If CW_(p)=CW_(max, p), the next higher allowed value for adjustingCW_(p) is CW_(max, p).

To determine the probability Z that the HARQ-ACK values corresponding tothe PDSCH transmission(s) in reference subframe k are determined asNACK, the following may be considered.

-   -   When the BS's transmission(s) for which HARQ-ACK feedback is        available start in the second slot of subframe k, HARQ-ACK        values corresponding to PDSCH transmission(s) in subframe k+1        are also used in addition to the HARQ-ACK values corresponding        to the PDSCH transmission(s) in subframe k.    -   When the HARQ-ACK values correspond to PDSCH transmission(s) on        an LAA SCell that are assigned by a (E)PDCCH transmitted on the        same LAA SCell,    -   If no HARQ-ACK feedback is detected for a PDSCH transmission by        the BS, or if the BS detects ‘DTX’ state, ‘NACK/DTX’ state, or        ‘any’ state, it is counted as NACK.    -   When the HARQ-ACK values correspond to PDSCH transmission(s) on        an LAA SCell that are assigned by a (E)PDCCH transmitted on        another serving cell,    -   If the HARQ-ACK feedback for a PDSCH transmission is detected by        the BS, the ‘NACK/DTX’ state or the ‘any’ state is counted as        NACK and the ‘DTX’ state is ignored.    -   If no HARQ-ACK feedback is detected for a PDSCH transmission by        the BS,    -   If PUCCH format 1b with channel selection, which is configured        by the BS, is expected to be used by the UE, the ‘NACK/DTX’        state corresponding to ‘no transmission’ is counted as NACK, and        the ‘DTX’ state corresponding to ‘no transmission’ is ignored.        Otherwise, the HARQ-ACK for the PDSCH transmission is ignored.    -   When a PDSCH transmission has two codewords, the HARQ-ACK value        of each codeword is considered separately.    -   Bundled HARQ-ACKs across M subframes are considered as M        HARQ-ACK responses.

If the BS transmits transmissions including a PDCCH/EPDCCH with DCIformat 0A/0B/4A/4B and not including a PDSCH that are associated withthe channel access priority class p on a channel starting from time to,the BS maintains the CW value CW_(p) and adjusts CW_(p) for thetransmissions before step 1 of the procedure described in clause 2.2.1(i.e., before performing the CAP) according to the following steps.

1> For every priority class p∈{1, 2,3,4}, CW_(p) is set to CW_(min, p).

2> If less than 10% of the UL transport blocks scheduled for the UE bythe BS according to a Type 2 CAP (which will be described in clause2.3.1.2) in a time interval from to and t₀+T_(CO) are receivedsuccessfully, CW_(p) for every priority class p∈{1, 2, 3, 4} increasesto a next higher allowed value, and step 2 remains. Otherwise, step 1proceeds.

The calculation of T_(CO) will be described in clause 2.3.1.

If CW_(p)=CW_(max,) p is consecutively used K times to generateN_(init), CW_(p) is reset to CW_(min, p) only for the priority class pfor which CW_(p)=CW_(max, p) is consecutively used K times to generateN_(init). In this case, K is selected by the BS from a set of values {1,2, . . . , 8} for each priority class p∈{1, 2,3, 4}.

2.2.4. Energy Detection Threshold Adaptation Procedure

A BS accessing a carrier on which LAA SCell(s) transmission(s) areperformed may set an energy detection threshold (X_(Thresh)) to be lessthan or equal to a maximum energy detection threshold X_(Thresh_max).

The maximum energy detection threshold X_(Thresh_max) is determined asfollows.

-   -   If the absence of any other technologies sharing the carrier can        be guaranteed on a long term basis (e.g., by level of        regulation),

$X_{{Thesh}\_\max} = {\min\begin{Bmatrix}T_{\max} & {{{+ 10}\mspace{14mu}{dB}},} \\X_{r} & \;\end{Bmatrix}}$

-   -   X_(r) is a maximum energy detection threshold defined by        regulatory requirements in dBm when such requirements are        defined. Otherwise, X_(r)=T_(max)+10 dB.    -   Otherwise,

$X_{{Thres}\_\max} = {\max\begin{Bmatrix}{{{- 72} + {{10 \cdot \log}\; 10( {{BW}\;{{MHz}/20}\mspace{14mu}{MHz}} ){dB}\; m}},} \\{\min\begin{Bmatrix}{T_{\max},} \\{{T_{\max} - T_{A} + ( {P_{H} + {{10 \cdot \log}\; 10( {{BW}\;{{MHz}/20}\mspace{14mu}{MHz}} )} - P_{TX}} )}\;}\end{Bmatrix}}\end{Bmatrix}}$

-   -   Each variable is defined as follows:        -   T_(A)=10 dB for transmission(s) including PDSCII;        -   T_(A)=5 dB for transmissions including discovery signal            transmission(s) and not including PDSCII;        -   P_(it)=23 dBm;        -   P_(TX) is the set maximum eNB output power in (Elm for the            earrilT            -   eNB uses the set maximum transmission power over a                single carrier irrespective of whether single carrier or                multi-cattier transmission is employed        -   T_(max)(dBm)=10·log 10(3.16228·10⁻⁸ (mW/MHz)·BWMHz (MHz))    -   BWMHz is the single carrier bandwidth in MHz

2.2.5. Channel Access Procedure for Transmission(s) on Multiple Carriers

A BS may access multiple carriers on which LAA Scell(s) transmission(s)are performed according to one of the following Type A or Type Bprocedures.

2.2.5.1. Type A Multi-Carrier Access Procedures

A BS may perform channel access on each carrier c_(i)∈C according to theaforementioned procedures, where C is a set of carriers on which the BSintends to transmit, and i=0, 1, . . . , q−1, where q is the number ofcarriers on which the BS intends to transmit.

The counter N described in clause 2.2.1 (i.e., the counter N consideredin the CAP) is determined for each carrier c_(i). The counter for eachcarrier is denoted as N_(c) _(i) . N_(c) _(i) is maintained according toclause 2.2.5.1.1 or 2.2.5.1.2.

2.2.5.1.1. Type A1

The counter N described in clause 2.2.1 (i.e., the counter N consideredin the CAP) is independently determined for each carrier c_(i), and thecounter for each carrier is denoted as N_(c) _(i) .

When the BS ceases transmission on any one carrier c_(j)∈C for eachcarrier (where) c_(i)≠c_(j)), if the absence of any other technologiessharing the carrier cannot be guaranteed on a long term basis (e.g. bylevel of regulation), the BS may resume decreasing N_(c) _(i) when anidle slot is detected after waiting for a duration of 4·T_(sl), or afterreinitializing N_(c) _(i) .

2.2.5.1.2. Type A2

The counter N may be determined as described in clause 2.2.1 for eachcarrier c_(j)∈C, and the counter for each carrier is denoted as N_(c)_(j) , where c_(j) is a carrier having the largest CW_(p) value. Foreach carrier c_(i), N_(c) _(i) =N_(c) _(j) .

When a BS ceases transmission on any one carrier for which N_(c) _(i) isdetermined, the BS reinitializes N_(c) _(i) for all carriers.

2.2.5.2. Type B Multi-Carrier Access Procedure

A carrier c_(j)∈C may be selected by a BS as follows.

-   -   The BS uniformly randomly selects c_(j) from C before performing        transmission on multiple carriers c_(i)∈C, or    -   The BS selects c_(j) no more frequently than once every 1        second.

C is a set of carriers on which the BS intends to transmit, and i=0, 1,. . . , q−1, where q is the number of carriers on which the BS intendsto transmit.

To perform transmission on the carrier c_(j), the BS performs channelaccess on the carrier c₁ according to the procedures described in clause2.2.1 with the following modifications, which will be described in2.2.5.2.1 or 2.2.5.2.2.

To perform transmission on a carrier c_(i)≠c_(j) among carriers c_(i)∈C,

For each carrier c_(i), the BS senses a carrier c_(i) for at least asensing interval T_(mc)=25 us immediately before transmission on thecarrier c_(j). Then, the BS may transmit on the carrier c_(i)immediately after sensing the carrier c_(i) to be idle for at least thesensing interval T_(mc). The carrier c_(i) is considered to be idle forT_(mc) if the channel is sensed to be idle during all the time durationsin which such sensing for determining the idle state is performed on thecarrier c_(j) in the given interval T_(mc).

The BS may not continuously perform transmission on the carrierc_(i)≠c_(j) (where c_(i) ∈C) for a period exceeding T_(mcot,p) given inTable 6, where T_(mcot,p) is determined based on channel accessparameters used for the carrier c_(j).

2.2.5.2.1. Type B1

A single CW_(p) value is maintained for a set of carriers C.

To determine CW_(p) for channel access on a carrier c_(j), step 2 of theprocedure described in clause 2.2.3 may be modified as follows.

-   -   If at least Z=80% of HARQ-ACK values corresponding to PDSCH        transmission(s) in reference subframe k of all carriers c_(i)∈C        are determined as NACK, CW_(p) for each priority class p∈{1, 2,        3, 4} increases to a next higher allowed value. Otherwise, step        1 proceeds.

2.2.5.2.2. Type B2

A CW_(p) value is maintained independently for each carrier c_(i) ∈Caccording to the procedure described in clause 2.2.3. To determineN_(init) for a carrier c_(j), the CW_(p) value of a carrier c_(j1) ∈C isused, where c_(j1) is a carrier with the largest CW_(p) value among allcarriers in the set C.

2.3. Uplink Channel Access Procedures

A UE and a BS scheduling UL transmission for the UE may perform thefollowing procedures to access channel(s) on which LAA SCell(s)transmission(s) are performed. In the following description, it isassumed that a UE and a BS are basically configured with a PCellcorresponding to an L-band and at least one SCell, each corresponding toa U-band. The U-band may be referred to as an LAA SCell. Hereinafter, adescription will be given of UL CAP operation applicable to the presentdisclosure. In this case, the UL CAP operation may be equally appliedwhen the UE and BS are configured only with U-bands.

2.3.1. Channel Access Procedure for Uplink Transmission(s)

A UE may access a carrier on which LAA SCell(s) UL transmission(s) areperformed according to either a Type 1 UL CAP or a Type 2 UL CAP. TheType 1 CAP will be described in clause 2.3.1.1, and the Type 2 CAP willbe described in clause 2.3.1.2.

If a UL grant scheduling PUSCH transmission indicates the Type 1 CAP,the UE performs the Type 1 CAP for transmitting transmissions includingthe PUSCH transmission unless specified otherwise in this clause.

If a UL grant scheduling PUSCH transmission indicates the Type 2 CAP,the UE performs the Type 2 CAP for transmitting transmissions includingthe PUSCH transmission unless specified otherwise in this clause.

The UE performs the Type 1 CAP for transmitting an SRS not includingPUSCH transmission. A UL channel access priority class p=1 is used forSRS transmission including no PUSCH.

TABLE 10 Channel Access Priority allowed CW_(p) Class (p) m_(p)CW_(min, p) CW_(max, p) T_(ulm cot, p) sizes 1 2 3 7 2 ms {3, 7}  2 2 715 4 ms {7, 15} 3 3 15 1023 6 ms or {15, 31, 63, 127, 10 ms 255, 511,1023} 4 7 15 1023 6 ms or {15, 31, 63, 127, 10 ms 255, 511, 1023} NOTE1:For p = 3.4, T_(ulm cot, p) = 10 ms if the higher layer parameterabsenceOfAnyOtherTechnology-r14 or absenceOfAnyOtherTechnology-r16 isprovided, otherwise, T_(ulm cot, p) = 6 ms. NOTE 2: When T_(ulm cot, p)= 6 ms it may be increased to 8 ms by inserting one or more gaps. Theminimum duration of a gap shall be 100 us. The maximum duration beforeincluding any such gap shall be 6 ms.

When the ‘UL configuration for LAA’ field configures a ‘UL offset’ l anda ‘UL duration’ d for subframe n,

If the end of UE transmission occurs in or before subframe n+l+d−1, theUE may use the Type 2 CAP for transmission in subframe n+l+i (where i=0,1, . . . , d−1).

When the UE is scheduled to perform transmission including a PUSCH in aset of subframes n₀, n₁, . . . , n_(w-1) using PDCCH DCI format 0B/4B,if the UE is incapable of accessing a channel for transmission insubframe n_(k), the UE shall attempt to make a transmission in subframen_(k+1) according to the channel access type indicated by DCI, wherek∈{0, 1, . . . w−2}, and w is the number of scheduled subframesindicated by the DCI.

When the UE is scheduled to perform transmission including a PUSCHwithout gaps in a set of subframes n₀, n₁ . . . , n_(w-1) using one ormore PDCCH DCI Format 0A/0B/4A/4B, if the UE performs transmission insubframe n_(k) after accessing a carrier according to one of the Type 1or Type 2 UL CAPs, the UE may continue transmission in subframes aftern_(k), where k∈{0, 1, . . . w−1}.

If the start of a UE transmission in subframe n+1 immediately followsthe end of a UE transmission in subframe n, the UE is not expected to beindicated with different channel access types for the transmissions inthe subframes.

When the UE is scheduled to perform transmission without gaps insubframes n₀n₁ . . . , n_(w-1) using one or more PDCCH DCI Format0A/0B/4A/4B, if the UE stops transmitting during or before subframen_(k1) (where k1∈{0, 1, . . . w−2}), and if the UE senses that thechannel is continuously idle after stopping the transmission, the UE maytransmit after subframe n_(k2) (where k2 ∈{1, . . . w−1}) using the Type2 CAP. If the UE senses that the channel is not continuously idle afterstopping the transmission, the UE may transmit after subframe n_(k2)(where k2 ∈{1, . . . w−1}) using the Type 1 CAP with a UL channel accesspriority class indicated by DCI corresponding to subframe n_(k2).

When the UE receives a UL grant, if the DCI indicates the start of PUSCHtransmission in subframe n using the Type 1 CAP, and if the UE has anongoing Type 1 CAP before subframe n,

-   -   If a UL channel access priority class value p₁ used for the        ongoing Type 1 CAP is greater than or equal to a UL channel        access priority class value p₂ indicated by the DCI, the UE may        perform the PUSCH transmission in response to the UL grant by        accessing the carrier based on the ongoing Type 1 CAP.    -   If the UL channel access priority class value p₁ used for the        ongoing Type 1 CAP is smaller than the UL channel access        priority class value p₂ indicated by the DCI, the UE terminates        the ongoing CAP.

When the UE is scheduled to transmit on a set of carriers C in subframen, if UL grants scheduling PUSCH transmissions on the set of carriers Cindicate the Type 1 CAP, if the same ‘PUSCH starting position’ isindicated for all carriers in the set of carriers C, and if the carrierfrequencies of the set of carriers C are a subset of one of thepredetermined carrier frequency sets,

-   -   The UE may perform transmission on a carrier c_(i)∈C using the        Type 2 CAP.    -   If the Type 2 CAP is performed on the carrier c_(i) immediately        before the UE performs transmission on a carrier c_(j) ∈C (where        i≠j), and    -   If the UE has accessed the carrier c_(j) using the Type 1 CAP,    -   The UE selects the carrier c_(j) uniformly and randomly from the        set of carriers C before performing the Type 1 CAP on any        carrier in the set of carriers C.

When the BS has transmitted on the carrier according to the CAPdescribed in clause 2.2.1, the BS may indicate the Type 2 CAP in DCI ofa UL grant scheduling transmission including a PUSCH on a carrier insubframe n.

Alternatively, when the BS has transmitted on the carrier according tothe CAP described in clause 2.2.1, the BS may indicate using the ‘ULconfiguration for LAA’ field that the UE may perform the Type 2 CAP fortransmission including a PUSCH on a carrier in subframe n.

Alternatively, when subframe n occurs within a time interval that startsat to and ends at t₀+T_(CO), the eNB may schedule transmission includinga PUSCH on a carrier in subframe n, which follows transmission by the BSon a carrier with a duration of T_(short_ul)=25 us, whereT_(CO)=T_(m,cot,p)+T_(g). The other variables are defined as follows.

-   -   t₀: a time instant when the BS starts transmission    -   T_(mcot,p): a value determined by the BS as described in clause        2.2    -   T_(g): the total duration of all gaps greater than 25 us that        occur between DL transmission from the BS and UL transmission        scheduled by the BS and between any two UL transmissions        scheduled by the BS starting from t₀

The BS schedules UL transmissions between t₀ and t₀+T_(CO) inconsecutive subframes if the UL transmissions are capable of beingscheduled contiguously.

For a UL transmission on a carrier that follows a transmission by the BSon the carrier within a duration of T_(short_ul)=25 us, the UE may usethe Type 2 CAP for the UL transmission.

If the BS indicates the Type 2 CAP for the UE in the DCI, the BSindicates the channel access priority class used to obtain access to thechannel in the DCI.

2.3.1.1. Type 1 UL Channel Access Procedure

A UE may perform transmission using the Type 1 CAP after sensing achannel to be idle during the slot durations of a defer duration T_(d)and after a counter N becomes zero in step 4. In this case, the counterN is adjusted by sensing a channel for additional slot duration(s)according to the following steps.

1) N is set to N_(init) (N=N_(init)), where N_(init) is a random numberuniformly distributed between 0 and CW_(p). Then, step 4 proceeds.

2) If N>0 and the UE chooses to decrease the counter, N is set to N−1(N=N−1).

3) The channel for the additional slot duration is sensed. If theadditional slot duration is idle, step 4 proceeds. Otherwise, step 5proceeds.

4) If N=0, the corresponding process is stopped. Otherwise, step 2proceeds.

5) The channel is sensed until either a busy slot is detected within anadditional defer duration T_(d) or all the slots of the additional deferduration T_(d) are detected to be idle.

6) If the channel is sensed to be idle during all the slot durations ofthe additional defer duration T_(d), step 4 proceeds. Otherwise, step 5proceeds.

The Type 1 UL CAP performed by the UE may be summarized as follows.

For UL transmission, a transmission node (e.g., UE) may initiate a CAPto operate in LAA SCell(s), each corresponding to a U-band cell (S1810).

The UE may randomly select a backoff counter N within a CW according tostep 1. In this case, N is set to an initial value, N_(init) (S1820).N_(init) may have a random value between 0 and CW_(p).

If the backoff counter value (N) is 0 (YES in S1830), the UE terminatesthe CAP according to step 4 (S1832). Then, the UE may transmit a Txburst (S1834). If the backoff counter value is non-zero (NO in S1830),the UE decreases the backoff counter value by 1 according to step 2(S1840).

The UE checks whether the channel of the LAA SCell(s) is idle (S1850).If the channel is idle (YES in S1850), the UE checks whether the backoffcounter value is 0 (S1830).

If the channel is not idle in S1850, that is, if the channel is busy (NOin S1850), the UE checks whether the corresponding channel is idleduring the defer duration T_(d) (longer than or equal to 25 usec), whichis longer than the slot duration (e.g., 9 usec), according to step 5(S1860). If the channel is idle (YES in S1870), the UE may resume theCAP.

For example, when the backoff counter value N_(init) is 10, if thechannel is determined to be busy after the backoff counter value isreduced to 5, the UE determines whether the channel is idle by sensingthe channel during the defer duration. In this case, if the channel isidle during the defer duration, the UE performs the CAP again startingat the backoff counter value of 5 (or at 4 by decreasing the backoffcounter value by 1), instead of configuring the backoff counter valueN_(init).

On the other hand, if the channel is busy during the defer duration (NOin S1870), the UE performs steps S1860 again to check whether thechannel is idle during a new defer duration.

When the UE does not transmit the transmission including the PUSCH onthe carrier on which the LAA SCell(s) transmission(s) are performedafter step 4 in the above procedure, the UE may transmit thetransmission including the PUSCH on the carrier if the followingconditions are satisfied:

-   -   When the UE is ready to perform the transmission including the        PUSCH and the channel is sensed to be idle at least in a slot        duration T_(sl); and    -   When the channel is sensed to be idle during all the slot        durations of the defer duration T_(d) immediately before the        transmission including the PUSCH.

If the channel is sensed not to be idle during the slot duration T_(sl)when the UE senses the channel after being ready to transmit or if thechannel is sensed not to be idle during any one of the slot durations ofthe defer duration T_(d) immediately before the intended transmissionincluding the PUSCH, the UE proceeds to step 1 after sensing the channelto be idle during the slot durations of the defer duration T_(d).

The defer duration T_(d) includes a duration T_(f) (=16 us) immediatelyfollowed by m_(p) consecutive slot durations. Here, each slot duration(T_(sl)) is 9 us long, and T_(f) includes an idle slot duration T_(sl)at the start thereof.

When the UE senses the channel during the slot duration T_(sl), if thepower detected by the UE for at least 4 us within the slot duration isless than an energy detection threshold X_(Thresh), the slot durationT_(sl) is considered to be idle. Otherwise, the slot duration T_(sl) isconsidered to be busy.

CW_(min,p)≤CW_(p)≤CW_(max,p) represents the CW. The adjustment of CW_(p)will be described in detail in clause 2.3.2.

CW_(min,p) and CW_(max,p) are selected before step 1 of the aboveprocedure.

m_(p), CW_(min,p), and CW_(max,p) are determined based on channel accesspriority classes signaled to the UE (see Table 9 above).

The adjustment of X_(Thresh) will be described in clause 2.3.3.

2.3.1.2. Type 2 UL Channel Access Procedure

If a UE uses the Type 2 CAP for transmission including a PUSCH, the UEmay transmit the transmission including the PUSCH immediately aftersensing a channel to be idle for at least a sensing intervalT_(short_ul)=25 us T_(short_ul) includes a duration T_(f)=16 usimmediately followed by one slot duration T_(sl)=9 us, and T_(f)includes an idle slot duration T_(sl) at the start thereof. When thechannel is sensed to be idle during the slot durations of T_(short_ul),the channel is considered to be idle for T_(short_ul).

2.3.2. Contention Window Adjustment Procedure

If a UE transmits transmissions using the Type 1 channel accessprocedure that are associated with the channel access priority class pon a carrier, the UE maintains the CW value CW_(p) and adjusts CW_(p)for the transmissions before step 1 of the procedure described in clause2.3.1 (i.e., before performing the CAP) according to the followingsteps.

-   -   If the value of a new data indicator (NDI) for at least one HARQ        process associated with HARQ_ID_ref is toggled,    -   For every priority class p∈{1, 2, 3, 4}, CW_(p) is set to        CW_(min,p).    -   Otherwise, CW_(p) for every priority class p∈{1, 2, 3, 4}        increases to a next higher allowed value.

Here, HARQ_ID_ref refers to the ID of a HARQ process of a UL-SCH inreference subframe n_(ref). Reference subframe n_(ref) is determined asfollows.

-   -   If the UE receives a UL grant in subframe n_(g), subframe n_(w)        is the most recent subframe before subframe n_(g)-3 in which the        UE has transmitted a UL-SCH using the Type 1 channel access        procedure.    -   If the UE performs transmission including the UL-SCH without        gaps starting from subframe no and in subframes n₀, n₁, . . . ,        n_(w), reference subframe n_(ref) is subframe n₀.    -   Otherwise, reference subframe n_(ref) is subframe n_(w).

When the UE is scheduled to perform transmission including a PUSCHwithout gaps in a set of subframes n₀, n₁, . . . , n_(w-1) using theType 1 channel access procedure, if the UE is unable to perform anytransmission including the PUSCH in the subframe set, the UE maymaintain the value of CW_(p) for every priority class p∈{1, 2, 3, 4}without any changes.

If the reference subframe for the last scheduled transmission is alson_(ref), the UE may maintain the value of CW_(p) for every priorityclass p∈{1, 2, 3, 4} to be the same as that for the last scheduledtransmission including the PUSCH using the Type 1 channel accessprocedure.

If CW_(p)=CW_(max, p), the next higher allowed value for adjustingCW_(p) is CW_(max, p).

If CW_(p)=CW_(max, p) is consecutively used K times to generateN_(init), CW_(p) is reset to CW_(min, p) only for the priority class pfor which CW_(p)=CW_(max, p) is consecutively used K times to generateN_(init). In this case, K is selected by the UE from a set of values {1,2, . . . , 8} for each priority class p∈{1, 2, 3, 4}.

2.3.3. Energy Detection Threshold Adaptation Procedure

A UE accessing a carrier on which LAA Scell(s) transmission(s) areperformed may set an energy detection threshold (X_(Thresh)) to be lessthan or equal to a maximum energy detection threshold X_(Thresh_max).

The maximum energy detection threshold X_(Thresh_max) is determined asfollows.

-   -   If the UE is configured with a higher layer parameter        “maxEnergyDetectionThreshold-r14’,    -   X_(Thresh_max) is set equal to a value signaled by the higher        layer parameter.    -   Otherwise,    -   The UE shall determine X′_(Thresh_max) according to the        procedure described in clause 2.3.3.1.    -   If the UE is configured with a higher layer parameter        ‘maxEnergyDetectionThresholdOffset-r14’    -   X_(Thresh_max) is set by adjusting X′ Thresh_max according to an        offset value signaled by the higher layer parameter.    -   Otherwise,    -   The UE sets X_(Thresh_max)=X′_(Thresh_max).

2.3.3.1. Default Maximum Energy Detection Threshold ComputationProcedure

If a higher layer parameter ‘absenceOfAnyOtherTechnology-r14’ indicatesTRUE,

${X^{\prime}}_{{Thesh}\_\max} = {\min{\begin{Bmatrix}T_{\max} & {{{+ 10}\mspace{14mu}{dB}},} \\X_{r} & \;\end{Bmatrix}.}}$

-   -   X_(r) is a maximum energy detection threshold defined by        regulatory requirements in dBm when such requirements are        defined. Otherwise, X_(r)=T_(max)+10 dB.

Otherwise,

${X^{\prime}}_{{Thres}\_\max} = {\max\begin{Bmatrix}{{{- 72} + {{10 \cdot \log}\; 10( {{BW}\;{{MHz}/20}\mspace{14mu}{MHz}} ){dB}\; m}},} \\{\min\begin{Bmatrix}{T_{\max},} \\{{T_{\max} - T_{A} + ( {P_{H} + {{10 \cdot \log}\; 10( {{BW}\;{{MHz}/20}\mspace{14mu}{MHz}} )} - P_{TX}} )}\;}\end{Bmatrix}}\end{Bmatrix}}$

-   -   Each variable is defined as follows:        -   T_(A)=10 dB        -   P_(H)−23 dBm,        -   P_(TX) is the set to the a hie of P_(CMAX_He) as destined m            3GPP TS:6.101.        -   T_(max) (dBm)=10·log 10 (3.16228·10⁻⁸ (mW/MHz)·BWMHz (MHz))            -   BWMHz is the single carrier bandwidth in MHz.

2.4. Subframe/Slot Structure Applicable to U-band System

FIG. 19 is a diagram illustrating a partial transmission time interval(TTI) or a partial subframe/slot applicable to the present disclosure.

In the Rel-13 LAA system, a partial TTI is defined using the DwPTS tomake the best use of a maximum channel occupancy time (MCOT) duringtransmission of a DL Tx burst and support continuous transmission. Thepartial TTI (or partial subframe) refers to an interval in which asignal is transmitted in a shorter period than the legacy TTI (e.g., 1ms) in PDSCH transmission

In the present disclosure, a starting partial TTI or a starting partialsubframe refers to a format in which some symbols located at the forepart of a subframe are left blank, and an ending partial TTI or anending partial subframe refers to a format in which some symbols locatedat the rear part of a subframe are left blank (whereas a complete TTI isreferred to as a normal TTI or a full TTI).

FIG. 19 illustrates various types of partial TTIs. In FIG. 12, the firstblock represents an ending partial TTI (or an ending partialsubframe/slot), the second block represents a starting partial TTI (or astarting partial subframe/slot), and the third block represents apartial TTI (or a partial subframe/slot) where some symbols located atthe fore and rear parts of a subframe are left blank. Here, a timeinterval obtained by removing a portion for signal transmission from anormal TTI is referred to as a transmission gap (Tx gap).

While FIG. 19 is based on DL operation, the present disclosure may beequally applied to UL operation. For example, the partial TTI structureshown in FIG. 19 is applicable to PUCCH and/or PUSCH transmission.

3. Proposed Embodiments

Hereinafter, the configurations according to the present disclosure willbe described in detail based on the above-described technical features.The details described above in clauses 1 and 2 may be applied to theembodiments of the present disclosure. For example, operations,functions, terms, etc. not defined regarding the embodiments of thepresent disclosure may be executed or explained based on the details inclauses 1 and 2.

As described above, as many communication devices have required highcommunication capacity, the necessity for efficient use of limitedfrequency bands has increased in next generation wireless communicationsystems.

For example, a method of using unlicensed bands in traffic offloading isdiscussed in cellular communication systems including the LTE system andthe NR system. Such an unlicensed band may be referred to as a U-band.The U-band may include the 2.4 GHz unlicensed band, which is commonlyused in the conventional Wi-Fi system, and the 5/6 GHz band, which newlyattracts attention.

Basically, it is assumed that each communication node competes withother communication nodes to perform wireless transmission and receptionin U-bands. Thus, before transmitting a signal, each communication nodeneeds to perform channel sensing to check whether other communicationnodes perform signal transmission. This operation may be referred to aslisten before talk (LBT) or a channel access procedure (CAP). Inparticular, an operation of checking whether other communication nodesperform signal transmission may be referred to as carrier sensing (CS).When it is determined that there is no communication node performingsignal transmission, it may be said that clear channel assessment (CCA)is confirmed.

The above description is equally applied to the LTE or NR wirelesscommunication system. Specifically, a BS or a UE in the LTE or NRwireless communication system needs to perform the CAP to transmit asignal in a U-band. In addition, when the BS or UE in the LTE or NRwireless communication system performs signal transmission, othercommunication nodes (e.g., Wi-Fi node, etc.) also need to perform theCAP to avoid causing interference to the BS or UE performing the signaltransmission.

For example, in Wi-Fi specifications (801.11ac), a CCA threshold of −62dBm is defined for a non-Wi-Fi signal, and a CCA threshold of −82 dBm isdefined for a Wi-Fi signal. That is, when a station (STA) or an accesspoint (AP) receives a non-Wi-Fi signal with power over −62 dBm, the STAor AP is prohibited to perform signal transmission to avoid causinginterference.

In the LAA system, a carrier bandwidth is limited to 20 MHz inconsideration of a Wi-Fi system coexisting in the same bands. The reasonfor this is that the Wi-Fi system determines whether a channel is idleor busy on a 20 MHz basis. Exceptionally, additional LAA operation in a10 MHz bandwidth (BW) is allowed for bands where there are no coexistingWi-Fi systems.

In the NR, an SCS larger than 15 kHz has been introduced. Thus, themaximum BW of the NR may be greater than the maximum BW of the LTEwireless communication system, 20 MHz. For example, when the SCS is 15kHz, the carrier BW may be set to a maximum of 50 MHz. When the SCS is30 kHz, the carrier BW may be set to a maximum of 100 MHz. As anotherexample, when the SCS is 30 kHz, the carrier BW may be set to a maximumof 50 MHz. When the SCS is 60 kHz, the carrier BW may be set to amaximum of 100 MHz.

Depending UE capability, there may be a UE operating in a BW smallerthan the maximum carrier BW managed by a network. In consideration ofsuch a UE, a BS in the NR wireless communication system may configurefor the UE a BWP smaller than a managed carrier BW.

The various embodiments of the present disclosure relate to BWPoperations in U-bands. For example, the embodiments are directed to aBWP configuration and activation method in consideration of aheterogeneous RAT such as Wi-Fi, LAA, etc., a channel occupancy time(COT) sharing method between DL and UL, a method of transmitting a dataand/or control channel per BWP, and the like.

For DL operation in NR-unlicensed (NR-U) bands, the following optionsfor BWP-based operation within a carrier with a BW larger than 20 MHzmay be considered.

-   -   Option 1a: Multiple BWPs are configured. Multiple BWPs are        activated. A PDSCH is transmitted on one or more BWPs.    -   Option 1b: Multiple BWPs are configured. Multiple BWPs are        activated. A PDSCH is transmitted on a single BWP.    -   Option 2: Multiple BWPs can be configured. A single BWP is        activated. A gNB transmits a PDSCH on a single BWP if CCA is        successful for the whole BWP.    -   Option 3: Multiple BWPs can be configured. A single BWP is        activated. A gNB transmits a PDSCH on a part or the entirety of        a single BWP where the gNB succeeds in CCA.

In the embodiments of the present disclosure, a UE may be configuredwith one of Options 1a, 1b, 2 and 3 unless specified otherwise. Inparticular, a UE may be configured with Option 3. However, theembodiments of the present disclosure are not limited to theaforementioned options.

FIG. 20 is a diagram illustrating a signal transmission and receptionmethod between a UE and a BS in a U-band applicable to the presentdisclosure.

Referring to FIG. 20, the BS may configure a set of BWPs on carrier(s)for the UE (S2001). In other words, the BS may configure a set of BWPson carrier(s) and transmit information on the configured BWP set to theUE. The UE may receive the information on the BWP set from the BS. TheBWP set may include at least one BWP corresponding to an active BWP forthe UE.

The carrier may include a U-band or an unlicensed carrier (U-carrier).In addition, one or more BWPs may be configured on one carrier.

The BS or UE may perform a CAP for performing communication in theU-band (S2003). Here, the CAP may be performed for each CAP BW. The CAPBW refers to the minimum (frequency) unit/band of the CAP performed bythe BS or UE. The CAP BW may be referred to as an LBT BW. The CAP BW maybe referred to as a CAP sub-band. The CAP BW may be referred to as anLBT sub-band as well. In the present specification, such terms may beinterchangeably used.

The CAP BW may be configured independently for each carrier (or carriergroup) and/or BWP (or BWP group). Alternatively, the CAP BW may beconfigured commonly for all carriers (or carrier groups) and/or BWPs (orBWP groups).

The BS or UE may perform BWP-related operations based on CAP results(S2005).

The BWP-related operations according to the embodiments of thedisclosure may include, for example, active BWP indication, DL-UL COTsharing, control/data channel generation/transmission, etc. Hereinafter,the details of each embodiment will be described.

3.1. BWP Configuration Method

3.1.1. BWP Configuration in Unit of BW Length Determined Based on Typeof Coexisting Heterogeneous RAT

FIG. 21 is a diagram illustrating BWPs included in a BWP configurationapplicable to the present disclosure.

In FIG. 21, it is assumed that a BS manages a continuous carrier BW of60 MHz. For example, a BWP configuration configurable by the BS for a UEmay include three BWPs each having a 20 MHz BW (BWPs 0/1/2), two BWPseach having a 40 MHz BW (BWPs 3/4), and one BWP having a 60 MHz BW (BWP5). The BS may configure some or all of the BWPs for the UE.

Although the minimum length of the BWP is assumed to be 20 MHz in thepresent disclosure, the present disclosure is not limited thereto. Theminimum length of the BWP may vary depending on implementation. Forexample, the minimum length of the BWP may depend on the type of acoexisting RAT. That is, when the BS configures the BWP, the BS maylimit the minimum BWP unit to have a predetermined BW length byconsidering a heterogeneous RAT. This limitation may be applied not onlyto the present embodiment but also to other embodiments of the presentdisclosure, which will be described later. It will be understood bythose skilled in the art.

When the BS is allowed to configure the BWP in a unit of 40 MHz, if a 20MHz BW included in the corresponding BWP is occupied by Wi-Fi, it may beerroneously determined that the entirety of a 40 MHz BWP is occupied byWi-Fi. This is because the Wi-Fi/LAA system determines whether a channelis idle or busy on a 20 MHz basis as described above. Therefore, the BSin a wireless communication system coexisting with the Wi-Fi/LAA systemmay limit the minimum BWP unit to 20 MHz.

The BS may configure the BWP over consecutive frequency bands. Asdescribed above, it is assumed in FIG. 21 that the BS manages thecontinuous 60 MHz carrier BW. In this case, the BS may allocate the UEsome or all of the 6 BWPs: three BWPs each having the 20 MHz BW; twoBWPs each having the 40 MHz BW; and one BWP having the 60 MHz BW.

A DL BWP and a UL BWP may be paired with each other. In this pairing,PUCCH transmission after PDSCH reception, PUSCH transmission after a ULgrant, or reporting after measuring CSI/RRM (radio resource measurement)may be considered.

For example, the same BWPs may be paired as the DL BWP and the UL BWP.Referring to FIG. 21, when BWP 0 is set to the DL BWP, the UL BWP pairedwith the DL BWP may also be BWP 0.

As another example, when the DL BWP is greater than 20 MHz, at least oneUL BWP equal to or included in the DL BWP may be paired with the DL BWP.

Referring again to FIG. 21, when BWP 3 is set to the DL BWP, the UL BWPpaired with the DL BWP may correspond to at least one BWP included inBWP 3, i.e., BWP 0, BWP 1, and/or BWP 3. In particular, the pairingaccording to the present disclosure is advantageous in terms of COTsharing between the BS and UE, which will be described in clause 3.3.

In the present disclosure, the CAP BW may refer to the minimum unit ofthe CAP performed by the BS or UE as described above. Each of BWPs 0, 1,and 2 illustrated in FIG. 21 may correspond to the CAP BW.

In the present specification, when the BS or UE succeeds in the CAP forBWP 0, BWP 1, and/or BWP 2 and transmits a DL/UL signal for BWP 0, BWP1, and/or BWP 2 for which the CAP is successful, it may be interpretedto mean that the operation described in 1) or 2) is performed.

-   -   1) The DL/UL signal for configured or activated BWP 0, BWP 1,        and/or BWP 2 is transmitted.    -   2) Even if BWP 0, BWP 1, and/or BWP 2 is not configured or        activated, the DL/UL signal is transmitted for a BW        corresponding to BWP 0, BWP 1, and/or BWP 2. Specifically, it is        assumed BWP 3, BWP 4, and/or BWP 5 is configured or activated.        Referring again to FIG. 21, each of BWPs 3, 4, and 5 includes        BWP 0, BWP 1, and/or BWP 2. In this example, when the BS or UE        succeeds in the CAP for BWP 0, BWP 1, and/or BWP 2 and transmits        a DL/UL signal for BWP 0, BWP 1, and/or BWP 2 for which the CAP        is successful, it may mean that the transmitted DL/UL signal is        for BWP 0, BWP 1, and/or BWP 2 respectively included in        configured or activated BWP 3, BWP 4, and/or BWP 5 rather than        for configured or activated BWP 3, BWP 4, and/or BWP 5.

3.1.2. BWP Configuration in Unit Different from BW Unit for PerformingCAP

This embodiment is directed to operation from the perspective of a BS ora UE. In particular, the operation from the perspective of the BS willbe described in the present embodiment.

The BS may configure a CAP BW with a predetermined unit but configure aBWP independently of the CAP BW. The predetermined unit for the CAP BWmay be determined in consideration of a coexisting heterogeneous RAT.For example, the BS in a wireless communication system coexisting withthe Wi-Fi/LAA system may configure a CAP on a 20 MHz basis. The BWP maybe configured independently of the CAP BW as described above. This isbecause the BWP may be configured UE-specifically.

It is assumed that when a 10 MHz BWP is configured or activated, a 5 MHzBW in the 10 MHz BWP belongs to one CAP BW, and the remaining 5 MHz BWbelongs to another CAP BW. In this case, the BS and/or UE may transmitdata in the corresponding BWP only when succeeding in the CAP for thetwo CAP BWs. As a result, the transmission probability may decrease.

To solve such a problem, when the BW of a configured and/or activatedBWP is less than the CAP BW, the corresponding BWP may be confined toone CAP BW. This may be generalized as follows: when a configured and/oractivated BWP is B MHz, the corresponding BWP may be confined in a BWPincluding ceiling {B/20} BWs, each corresponding to 20 MHz. Here,ceiling 0 is a ceiling function for calculating a minimum integergreater than or equal to a certain real number. In the presentembodiment, the CAP BW may be replaced with the minimum BWP unit and/or20 MHz.

Considering occupied BWs and regulations such as power spectral density,etc., the UL BWP may also be configured in a predetermined unit. Forexample, the UL BWP may also be configured on a 20 MHz basis.

When the DL BWP is less than 20 MHz, the UL BWP paired with the DL BWPmay include the corresponding DL BWP.

For example, referring again to FIG. 21, when the DL BWP is a BWP havinga 5 MHz BW in BWP 0, the UL BWP paired with the DL BWP may be BWP 0.

When the DL BWP is greater than 20 MHz, the UL BWP paired with the DLBWP may be minimum BWPs, each of which corresponds to 20 MHz, includingthe corresponding DL BWP and/or some of the BWPs.

For example, referring again to FIG. 21, when a DL BWP of 30 MHzconsists of BWP 0 of 10 MHz and BWP 1 of 20 MHz, a UL BWP paired withthe DL BWP may be BWP 0, BWP 1, and/or BWP 3.

In the present disclosure, the minimum unit (i.e., the minimum length ofa BWP, the minimum unit of a CAP BW, etc.) may be determined based onthe numerology of a wireless communication network. In theabove-described embodiment, 20 MHz may vary depending on the numerologyof the wireless communication network. For example, considering that thenumerology of the NR system is determined by 15*2^(n), it may not be amultiple/divisor of 20 MHz.

Accordingly, 20 MHz in the above-described embodiment may be replacedwith, for example, a value closest to 20 MHz among values represented by15*2^((n*M)) (where n and M are natural numbers).

Alternatively, 20 MHz in the above-described embodiment may be replacedwith a value closest to and less than 20 MHz among values represented by15*2^((n*M)) (where n and M are natural numbers).

Alternatively, 20 MHz in the above-described embodiment may be replacedwith a value closest to and greater than 20 MHz among values representedby 15*2^((n*M)) (where n and M are natural numbers).

Further, 20 MHz in the above-described embodiment may be replaced withthe basic BW of a coexisting RAT. For example, when the basic BW of thecoexisting RAT is not 20 MHz (e.g., when the basic BW is 10 MHz, 2 GHz,etc.), 20 MHz may be replaced with the basic BW of the correspondingcoexisting RAT for implementation of the embodiments.

3.2. Active BWP Indication Method

As described above, a BS and/or a UE may perform a CAP for each BWP oreach CAP BW. Considering this operation of the BS and/or UE, an actuallyactivated BWP may vary depending on CAP results.

Currently, in the NR wireless communication system, a BS may inform a UEof an activated (or active) BWP in DCI in the case of PDSCHtransmission.

However, considering a case in which a BWP for transmitting ameasurement reference signal (RS) needs to be provided to an unscheduledUE or a case in which an activated BWP for PDCCH monitoring needs to beprovided, a method for a BS to inform a UE of an active BWP dynamicallyis required.

3.2.1. Method of Using Initial Signal

A BS may inform a UE of an active BWP through an initial signal. The UEmay perform blind detection for the initial signal. The UE may obtainthe active BWP from the initial signal detected by the blind detection.For example, the initial signal may include a CSI-RS, a DM-RS for aPDCCH, a group-common PDCCH, a PSS, an SSS, a PBCH-DMRS, etc.

For example, referring again to FIG. 21, an initial signal may betransmitted for each of BWPs 0, 1, and 2. When the UE is configured withBWP 3, if BWPs 0 and 1 are simultaneously activated or if initialsignals for both BWPs 0 and 1 are detected, the UE may know that BWP 3is activated.

As another example, an initial signal may be configured for each of BWPs0, 1, 2, 3, 4, and 5. Upon receiving individual initial signals, the UEmay know that BWP(s) corresponding to the individual initial signals areactivated.

As a further example, an initial signal transmitted for each of BWPs 0,1, and 2 may include information on an active BWP. That is, whendetecting the initial signal for BWP 0, the UE may know from informationincluded in the detected initial signal whether an actually activatedBWP is BWP 0, BWP 3, or BWP 5.

The transmission power per RE of the BS may vary depending on theactually activated BW (BWP). In this case, CSI/RRM measurement may beperformed for each Tx bust with the same transmission power.Alternatively, the CSI/RRM measurement may be performed for Tx burstswith the same active BWP.

For example, referring back to FIG. 21, it is assumed that BWP 0 isactivated for Tx burst 1 and BWP 3 is activated for Tx burst 2. In thiscase, the CSI and/or RRM measurement may be performed separately foreach Tx burst. The CSI and/or RRM measurement may not be based on theaverage of values measured for all Tx bursts. In addition, when the UEreports the measurement to the BS, the UE may report the measurement foreach active BWP instead of reporting the average.

Meanwhile, the CSI measurement may be divided into estimation forchannel terms and estimation for interference terms. The estimation forchannel terms may refer to estimation based on the signal strength froma serving cell, and the estimation for interference terms may meanestimation based on the signal strength of all interference signalsincluding noise.

In the CSI measurement, if multiple CAP BWs are present in one activeBWP, the interference terms may be estimated only from a Tx bursttransmitted from a serving BS. In this case, the interference terms maybe estimated separately for each CAP BW or CAP BW group. Here, the CAPBW or CAP BW group may imply a unit for estimating the interferenceterms. The CAP BW or CAP BW group may be predefined orconfigured/indicated by RRC signaling or L1 signaling.

3.3. DL-UL COT Sharing Method

FIGS. 22A to 23 are diagrams illustrating examples of COT sharingbetween DL and UL BWPs applicable to the present disclosure.Hereinafter, a description will be given of a DL-UL COT sharing methodwith reference to FIGS. 22A to 23.

In this embodiment, COT sharing may mean that one device shares itsoccupied COT with another device. For example, when one device obtains aCOT using CAT4 LBT (CAP), another device may share the COT using 25 usLBT (CAP) with a predetermined gap in a range that does not exceed theMCOT limit for a given priority class.

In describing the embodiments of the present disclosure, related termsare defined as follows.

-   -   CAP Type 1 (Type 1 CAP): Random backoff based CAP, Category 4        CAP (CAT 4 CAP/LBT)    -   CAP Type 2 (Type 2 CAP): CAP performed for predetermined time        (short time, for example, for 25 usec)    -   CAP Type 3 (Type 3 CAP): CAP where transmission starts without        performing CAP

In enhanced-licensed assisted access (eLAA) of LTE Rel-14, when a BSobtains a COT by performing the Type 1 CAP and shares a part of the COTwith associated UEs, the UEs may be allowed to transmit UL signals afterperforming the Type 2 CAP. In this case, since a channel occupied by theBS is shared with the UEs, the UEs may access to the channel with highprobability.

In further enhanced-licensed assisted access (FeLAA) of NR Rel-15, it isdiscussed that a UE initiates occupying a COT and share the occupied COTwith a BS. Further, it may also be considered that the BS and/or UEoccupies a channel for an eNB-initiated COT or a UE-initiated COT.

This embodiment relates to BWP operations in the above COT sharingsituation. For convenience of description, the embodiment is describedbased on the eNB-initiated COT, the embodiment is not limited thereto.That is, the embodiment is applicable to the UE-initiated COT as well.

In addition, the BS described in the present embodiment is not limitedto an eNB. That is, the BS may be replaced with a gNB, etc. Further, theType 2 CAP may be replaced with the Type 3 CAP in the followingembodiments.

3.3.1. Signal Transmission and Reception Method in DL-UL COT Sharing

COT sharing may be allowed between a DL BWP and a UL BWP pairedtherewith or between a DL BWP and a UL BWP smaller than or equal to theDL BWP. Here, the pairing between the DL BWP and UL BWP may be performedaccording the method described in clause 3.1. In this embodiment, a BWPmay be replaced with a BW corresponding to the BWP. That is, a DL BWPmay be replaced with a BW corresponding to the DL BWP, and a UL BWP maybe replaced with a BW corresponding to the UL BWP.

For example, the COT sharing shown in FIG. 22A is assumed. When a UE isscheduled with a PUSCH for BWP 3 (BWP 3 PUSCH), if the UE succeeds inthe Type 2 CAP in both BWPs 0 and 1, the UE may transmit the PUSCH inBWP 3. In the present embodiment, the UE scheduled with the BWP 3 PUSCHmay be interpreted to mean a UE scheduled with a PUSCH in a BWcorresponding to BWP 3.

As another example, the COT sharing showing in FIG. 22B is assumed. Whena UE is scheduled with a BWP 3 PUSCH, if the UE succeeds in the Type 2CAP only in BWP 0, the UE may transmit the PUSCH only in BWP 0. In thepresent embodiment, BWP 0 may be replaced with a CAP BW corresponding toBWP 0.

In this case, a PUSCH to be transmitted in BWP 1 may be punctured orrate-matched under consideration of UE processing complexity. The UE mayinform a BS that the PUSCH is punctured or rate-matched. Specifically,the UE may inform the BS that the PUSCH to be transmitted in BWP 1 ispunctured or rate-matched. To this end, for example, an initial signalor a DM-RS may be used. In other words, the UE may use the initialsignal or the DM-RS to inform the BS that the PUSCH to be transmitted inBWP 1 is punctured or rate-matched.

For a channel or a signal where stable transmission is important, asignal to be transmitted may be prepared for each configured BWP, andthe prepared signal may be transmitted based on CAP results. Here, thechannel or signal where stable transmission is important may include aPUCCH, a PRACH, an SRS, a PDCCH, etc.

For example, assuming that a UE transmits a PUCCH, the UE may separatelyprepare for a PUCCH for BWP 0 (BWP 0 PUCCH) and a PUCCH for BWP 1 (BWP 1PUCCH). After performing the CAP, the UE may transmit the PUCCH for aBWP for which the CAP is successful.

When the UE succeeds in the CAP for multiple CAP BWs, the UE maytransmit the PUCCH according to a predetermined method or rule.

For example, the UE may transmit a predetermined BWP PUCCH with a highpriority. Alternatively, the UE may randomly select at least one BWPfrom among BWPs for which the CAP is successful and transmit the PUCCHin the selected BWP or BW. Further, the UE may transmit PUCCHs for allBWPs for which the CAP is successful. In the present embodiment, a BWPmay be replaced with a BW corresponding to the BWP.

That is, when the UE succeeds in the CAP for both BWPs 0 and 1 in theabove example, the UE may transmit either the BWP 0 PUCCH or the BWP 1PUCCH according to predetermined priorities. Alternatively, the UE mayrandomly select one of BWP 0 and BWP 1 and transmit a PUCCH in theselected BWP. Further, the UE may transmit PUCCHs for both BWP 0 and BWP1.

When the present embodiment is applied to the UE-initiated COT, thePUSCH may be replaced with the PDSCH. In addition, when the presentembodiment is applied to the UE-initiated COT, the Type 2 CAP may bereplaced with the Type 1 CAP. That is, when the UE succeeds in the Type1 CAP, the present embodiment may be applied to UL transmissions to betransmitted.

In this case, the same COT may or may not be shared for DLtransmission(s) after the UL transmissions.

3.3.1.1. Resource Configuration for CAP BW

In the case of a channel or a signal where stable transmission isimportant, signal transmission may be prepared for each BWP or CAP BW asdescribed above. In addition, a BWP (or a CAP BW) in which transmissionis actually performed may vary depending on CAP results. As describedabove, the channel or signal where stable transmission is important mayinclude, for example, a PUCCH, a PRACH, an SRS, a PDCCH, etc.

This embodiment may be applied to both an eNB-initiated COT and aUE-initiated COT. Although the present embodiment is described based ona PUCCH, it is apparent that the embodiment is also applicable to aPRACH or an SRS.

When one or more CAP BWs are included in a configured or active BWP,whether a channel is idle or busy may vary for each CAP BW.

Thus, if transmission is allowed in some CAP BWs, one PUCCH resource maybe configured to correspond to the one or more CAP BWs. Multiplecandidates may be configured/indicated for one or more startingpositions with respect to time-domain resources in the same way as thosefor frequency-domain resources. That is, one PUCCH resource maycorrespond to a 2-dimensional resource in the time and frequencydomains. In the present disclosure, a plurality of PUCCH resources maybe preconfigured.

Among the plurality of PUCCH resources, an actually used PUCCH resourcemay be indicated. For example, the plurality of PUCCH resources may bepreconfigured by RRC signaling, and the actually used PUCCH resourceamong the plurality of PUCCH resources may be determined by UCI payload,L1 signaling, and/or PDCCH resource information.

For example, referring again to FIG. 21, one of the PUCCH resourcesconfigured for BWP 3 may correspond to a set of the following resources.

-   -   1) Starting symbol #A in a specific slot and specific RB(s) in        BWP 0 (i.e., a CAP BW included in BWP 3). Here, the slot index        of the specific slot may be indicated by DL assignment or common        DCI.    -   2) Starting symbol #B in a specific slot (or a specific starting        symbol in a slot after a slot including a resource corresponding        starting symbol #A) and specific RB(s) in BWP 0 (i.e., a CAP BW        included in BWP 3). Here, the slot index of the specific slot        may be indicated by DL assignment or common DCI.    -   3) Starting symbol #B in a specific slot (or a specific starting        symbol in a slot after a slot including a resource corresponding        starting symbol #A) and specific RB(s) in BWP 1 (i.e., a CAP BW        included in BWP 3). Here, the slot index of the specific slot        may be indicated by DL assignment or common DCI.

In other words, in the 2-dimensional (2-D) PUCCH resource configuration,at least one starting position may be configured in the time domain withrespect to a specific CAP BW. In addition, regardless of the specificCAP BW, a PUCCH resource may be configured for at least one CAP BW inthe frequency domain with respect to a specific time-domain startingposition.

The number of CAP BWs corresponding to one PUCCH resource may beinversely proportional to the number of time-domain starting positioncandidates. The reason for this is to maintain the amount of allocatedresources to be similar for each PUCCH resource.

That is, when there are a relatively large number of CAP BWscorresponding to one PUCCH resource, the PUCCH resource may beconfigured such that there are a relatively small number of time-domainstarting position candidates.

On the contrary, when there are a relatively small number of CAP BWscorresponding to one PUCCH resource, the PUCCH resource may beconfigured such that there are a relatively large number of time-domainstarting position candidates.

It is assumed that for a specific starting position, multiple CAP BWsare configured to correspond to a PUCCH resource. In this case, if theCAP for one or more CAP BWs is successful, CAP BW(s) to be actually usedfor transmission may be determined according to at least one of thefollowing standards or any combination thereof.

-   -   1) A CAP BW in which the highest (or lowest) Tx power is        configured/indicated/calculated    -   2) A CAP BW in which the highest (or lowest) CCA threshold is        configured/indicated/calculated    -   3) A CAP BW with the highest (or lowest) energy level    -   4) A CAP BW in which {CCA threshold—measured energy level} has        the highest (or lowest) value    -   5) A CAP BW with the highest priority when there is a        predetermined/preconfigured priority rule    -   6) A CAP BW in which a specific type of CAP is performed, i.e.,        a CAP BW in which the Type 1 CAP, the Type 2 CAP, or the Type 3        CAP is performed    -   7) All CAP BW(s) where the CAP is successful

3.3.2. Signal Transmission Method in DL-UL COT Sharing

When a BWP for prescheduled UL transmission within an eNB-initiated COTis larger than a DL BWP, a UE may perform the scheduled UL transmissionif the Type 1 CAP is successful. However, if the UE succeeds in the Type2 CAP for the UL BWP rather than the Type 1 CAP, the scheduled ULtransmission may be allowed in a BWP (or a BW corresponding to the BWP)smaller than the UL BWP. In this embodiment, a BWP may be replaced witha BW corresponding to the BWP.

For example, in FIG. 23, it is assumed that from the perspective of a UEscheduled with a UL BWP, a COT shared from a DL BWP includes the ULduration scheduled for the UE. That is, it is assumed that from theperspective of a UE scheduled with UL BWP 3, a COT shared from DL BWP 1includes the UL duration scheduled for the UE. In the presentembodiment, a BWP may be replaced with a BW corresponding to the BWP.

In this situation, if the UE succeeds in the Type 2 CAP for BWP 1, theUE may be allowed to transmit a PUSCH in BWP 1 by puncturing orrate-matching BWP 0. In the present embodiment, a BWP may be replacedwith a BW corresponding to the BWP. That is, BWP 0 may be replaced witha BW corresponding to BWP 0, and BWP 1 may be replaced with a BWcorresponding to BWP 1.

The UE may inform a BS that PUSCH puncturing or rate-matching isperformed. For example, the UE may inform the BS that a PUSCH ispunctured or rate-matched through the initial signal or DM-RS of thePUSCH.

When the present embodiment is applied to a UE-initiated COT, the PUSCHmay be replaced with the PDSCH. In addition, when the present embodimentis applied to the UE-initiated COT, the Type 2 CAP may be replaced withthe Type 1 CAP. That is, the present embodiment may be applied to ULtransmissions transmitted by a UE after success of the Type 1 CAP. Inthis case, the same COT may or may not be shared for DL transmission(s)after the UL transmissions.

3.4. Method for Control/Data Channel Configuration for Each BWP

This embodiment relates to a method of configuring a control channelsuch as a PDCCH/PUCCH and/or a data channel such as a PDSCH/PUSCH. Thatis, the present embodiment is directed to a method of configuring acontrol channel for transmitting a control signal and/or a data channelfor transmitting a data signal.

In particular, the present embodiment relates to a control and/or datachannel configuration method suitable when a control and/or data channelis scheduled in a frequency region greater than a CAP BW. In the presentembodiment, a signal may be mapped to a frequency region with a BWgreater than the CAP BW. The frequency region with the BW greater thanthe CAP BW may be, for example, an active BWP, but the presentdisclosure is not limited thereto.

As described above, the CAP BW refers to a unit in which a UE and/or aBS performs a CAP. Thus, the UE and/or BS may perform the CAP on a CAPBW basis in the frequency region with the BW greater than the CAP BW.The frequency region with the BW greater than the CAP BW may be, forexample, an active BWP.

Even when a data channel is scheduled in the frequency region greaterthan the CAP BW, data channel transmission may be allowed in some CAPBWs based on CAP results per CAP BW.

In this case, whether the transmission is allowed may be configuredand/or indicated in advance. Specifically, whether the data channeltransmission is allowed in some CAP BWs for which the CAP is successfulmay be configured and/or indicated in advance. Such a configurationand/or indication may be provided by RRC signaling, MAC CE signaling,and/or L1 signaling and/or any combination thereof.

When it is not configured/indicated, data transmission may be allowedonly if the CAP is successful for all CAP BWs included in the scheduleddata channel.

3.4.1. Control Channel Configuration Method

In this embodiment, a PDCCH is taken as an example of a control channel.

Time/frequency resource(s) for transmitting the PDCCH may be configuredin each CAP BW (or per minimum BWP unit). In contrast, a CAP BW (or aminimum BWP unit or a BWP) may be configured for each configuredtime/frequency resource. The time/frequency resource(s) for transmittingthe PDCCH may be referred to a control resource set (CORESET).

3.4.2. Data Channel Configuration Method

In this embodiment, a PDSCH/PUSCH is taken as an example of a datachannel.

-   -   Option 1: The transmission (or transport) block of the        PDSCH/PUSCH may be configured for each CAP BW. In the present        embodiment, a transmission block may be replaced with a code        block, a code block group, etc. In the present embodiment, a CAP        BW may be replaced with the minimum BWP unit.

When mapping the PDSCH/PUSCH to resources, a BS may performfrequency-first mapping. In this case, the BS may perform thefrequency-first mapping in one CAP BW and then perform thefrequency-first mapping in another CAP BW. In the present embodiment, aCAP BW may be replaced with the minimum BWP unit.

According to such a data mapping method, since the PDSCH/PUSCH may bemapped to multiple CAP BWs or minimum BWP units, success in some codeblocks/code block groups (CBGs) may be guaranteed even though some BWPsare not transmitted (i.e., the BWPs are punctured) due to CAP failure,thereby supporting efficient retransmission. In this case, a CBG-basedretransmission scheme may be used.

Further, when a CAP time (T1) is behind a predetermined PDSCH/PUSCHstart time (T2) such as a slot boundary (i.e., T1>T2), puncturing may beperformed for at least a time period of T1-T2. Accordingly, a datamapping method needs to be designed in consideration of such puncturing.

For example, referring again to FIG. 21, the data channel may beconfigured such that the PDSCH/PUSCH is transmitted in BWP 0 and BWP 1and in 14 symbols of slot #n. In this case, grouping may be performed onthe 14 symbol at intervals of N symbols, where N is a natural number.For example, assuming that N=2, data may be mapped to resources in thefollowing order: symbol 0/1 of BWP 0→symbol 0/1 of BWP 1→symbol 2/3 ofBWP 0→ . . . symbol 2/3 of BWP 1→ . . . .

Such mapping may be generalized as follows. When the data channel isconfigured such that the PDSCH/PUSCH is transmitted, the data channelmay be sequentially mapped to BWPs on a symbol group basis.

According to the proposed method, data loss caused by puncturing in thetime/frequency domain due to the CAP failure may be effectivelyrestored. In this case, the CBG-based retransmission scheme may be used.

-   -   Option 2: To transmit the data channel, one transmission block        (TB) may be configured in each BWP with a different redundancy        version (RV). By doing so, even though some BWPs are not        transmitted (i.e., the BWPs are punctured) due to CAP failure,        it may be restored.

Here, transmission per BWP may refer to transmission per CAP BW. Forexample, a different RV may be configured for each CAP BW included in anactive BWP. In the present embodiment, a CAP BW may be replaced with theminimum BWP unit.

Different RVs may have different RV indices. For example, referringagain to FIG. 21, when TBs are transmitted in BWP 0 and BWP 1, a TB withRV=0 and a TB with RV=3 (or 2) may be transmitted in BWP 0 and BWP 1,respectively.

Each RV index may be determined according to a predetermined method. Forexample, the RV index may be determined by scheduling DCI or configuredby a BWP (or CAP BW) index function.

-   -   Option 3: When some (or all) BWPs are not transmitted (i.e., the        BWPs are punctured) due to CAP failure, data on the        non-transmitted BWPs may be transmitted in next slot(s). In the        present disclosure, a BWP may be replaced with a CAP BW.

For example, referring again to FIG. 21, it is assumed that a specificTB is mapped to BWP 0/1/2 of slot #n. When a BS and/or a UE succeeds inthe CAP only for BWP 0, the BS and/or UE may transmit only data mappedto BWP 0 of slot #n. The BS and/or UE may transmit data mapped to BWP 1of slot #n in slot #n+1 and then transmit data mapped to BWP 2 of slot#n in slot #n+2.

This may be generalized as follows. When a BWP is determined to be busyby the CAP, the BS and/or UE may defer transmission of data mapped tothe busy BWP (through puncturing). Specifically, the BS and/or UE maytransmit the data mapped to the BWP, which is determined to be busy bythe CAP, in a certain time duration. Thereafter, the BS and/or UE maytransmit the rest of the data of which the transmission is deferred in anext time duration. Here, a time duration may include at least one slot.In the present embodiment, a BWP may be replaced with a CAP BW.

3.4.3. DM-RS Transmission Method

When a CAP time (T1) is behind a predetermined PDSCH/PUSCH start time(T2) such as a slot boundary (i.e., T1>T2), puncturing may be performedfor at least a time period of T1-T2. Accordingly, a data mapping methodneeds to be designed in consideration of such puncturing.

In an embodiment, the location of a DM-RS symbol may be determined asthe last symbol in the total data duration. Here, the last symbol may berepresented as symbol #Z. Symbol #Z may correspond to the limit ofdemodulation performance and puncturing loss. When a DM-RS is capable ofbeing transmitted in symbol #Z, the DM-RS may be transmitted bypuncturing the time period of T1-T2. However, if T1 is behind symbol #Z,all data in a corresponding slot may be dropped.

In another embodiment, the location of a DM-RS symbol may be shiftedaccording to the time at which the CAP succeeds. For example, referringagain to FIG. 21, when a data channel is configured such that the datachannel is transmitted in BWP 0 and BWP 1 and in 14 symbols of slot #n,the time at which a DM-RS is transmitted may vary depending on startingsymbols.

For example, the DM-RS symbol may be located as follows.

-   -   When the starting symbol is within symbols 0 to 3, the DM-RS is        transmitted in symbol 3.    -   When the starting symbol is within symbols 4 to 6, the DM-RS is        transmitted in symbol 6.    -   When the starting symbol is within symbols 7 to 10, the DM-RS is        transmitted in symbol 10.    -   When the starting symbol is within symbols 11 to 13, the DM-RS        is transmitted in symbol 13.

3.4.4. HARQ-ACK Bundling

It is assumed that a UE and/or a BS performs CB(G)-level HARQ-ACKbundling for TB(s) transmitted in multiple CAP BWs (or minimum BWPunits). In this case, the UE and/or BS may preferentially bundleHARQ-ACKs corresponding to CB(G)(s) transmitted in the same CAP BW.

For example, referring back to FIG. 21, it is assumed that TBstransmitted in BWP 3 includes CBG 0/1/2/3, CBG 0/1 belongs to BWP 0, andCBG 2/3 belongs to BWP 1.

In this case, the UE may perform bundling for each BWP. That is, whenthe UE reduce the size of a HARQ-ACK per CBG from 4 bits to 2 bits byperforming HARQ-ACK bundling for the TBs, the UE may perform bundling asfollows: (1-bit HARQ-ACK for CBG 0/1)+(1-bit HARQ-ACK for CBG 2/3).

3.4.5. Active BWP Change

As described above, an active BWP may be changed depending on thesuccess or failure of a CAP. If data transmission needs to be performedimmediately after the change of the active BWP, the implementation of atransmission node such as a BS, a UE, etc. may be more complicated.

To solve such a problem, a BS and/or a UE may transmit data in each CAPBW (or each minimum BWP unit) during K slot(s) (or X usec, i.e., SCSindependent time) after succeeding in the CAP.

For example, referring back to FIG. 21, even when the CAP is successfulfor BWP 3, data transmission in BWP 3 may start after data istransmitted during K slots (or X usec) in each of BWPs 0 and 1.

In this case, the BS may transmit information on BWPs for which the CAPis successful to the UE. For example, the BS may transmit common DCI orDL/UL scheduling DCI to the UE by including the information on the BWPsfor which the CAP is successful therein. In the present embodiment, aBWP or a CAP BW for which the CAP is successful may be replaced with aBWP or a CAP BW in which the BS intends to transmit a signal.

Here, the information on the corresponding BWPs or CAP BWs may includeinformation about a slot in which the DCI is transmitted, next Nslot(s), and/or slots in a DL/UL Tx burst.

For example, referring again to FIG. 21, it is assumed that the BSattempts DL transmission during slot #n to slot #n+4 after succeeding inthe CAP for BWP 0. Here, the DL transmission may be shared with ULtransmission.

The BS may inform the UE in common DCI or DL/UL scheduling DCI that datawill be transmitted in BWP 0 during slot #n to slot #n+4. The UE mayrecognize the CB/CBG/RV of a data channel transmitted in BWP 0 accordingto the embodiment described in clause 3.4.2.

The present embodiment may be applied not only to the frame structuredescribed in clause 3.4.2 but also to other normal frame structures.

Although the present embodiment is described based on the operation fromthe perspective of the BS, the embodiment is also applicable to UEoperation. When the present embodiment is applied to the UE, informationon BWPs for which the CAP is successful may be transmitted from the UEto the BS. Such information may be transmitted, for example, in aconfigured UL grant. When the present embodiment is applied to the UE, aBWP or a CAP BW for which the CAP is successful may be replaced with aBWP or a CAP BW in which the UE intends to transmit a signal.

3.5. Multi-BWP/Carrier CAP

In the LTE wireless communication system, when a CAP is performed formultiple carriers in LAA UL, a contention window size may bemanaged/executed for each carrier.

For example, when the Type 1 CAP is indicated and the same PUSCHstarting position is configured for carriers, the Type 1 CAP may beperformed for each carrier.

As another example, the Type 1 CAP may be indicated, and one carrier maybe selected from among carriers with the same PUSCH starting position.In this case, the Type 1 CAP may be performed only for the selectedcarrier, and the Type 2 CAP may be performed for the remaining carriersbefore the success of the Type 1 CAP for the selected carrier.

This embodiment relates to a CAP method in a multi-BWP/carrierenvironment when a carrier BW is set greater than the typical carrier BWof the LTE LAA system, 20 MHz. Although a UL case is considered in thepresent embodiment, it is apparent that the present embodiment isapplicable to both UL and DL.

3.5.1. CWS Adjustment and CAP on Multiple Carriers

When a BWP or a carrier is configured to have a BW greater than a CAPBW, the value of a CWS may be adjusted according to one of the followingmethods.

The following methods are classified according to which unit is used toadjust the CWS value. Which one of the following methods is applied,that is, which unit is used to adjust the CWS value (per BW) may bepredefined or determined by specific signaling. The specific signalingmay include RRC signaling, MAC CE signaling, and/or L1 signaling and/orany combination thereof

-   -   Method 1: CWS adjustment for each CAP BW    -   Method 2: CWS adjustment for each configured or active BWP

For example, when transmission failure is recognized for at least oneCAP BW with respect to data transmitted in a configured or active BWP,the CWS value may increase.

Alternatively, while the CWS is adjusted for each CAP BW in theconfigured or active BWP, the actual CWS value may be the maximum valueamong CWS values corresponding to CAP BWs included in the configured oractive BWP.

-   -   Method 3: CWS adjustment for each carrier

In this case, the CWS value may be maintained even if switching betweenBWPs is performed on a carrier.

The following options may be considered when a UE scheduled withmulti-carrier transmission performs a CAP. In particular, the followingoptions may be considered when the Type 1 CAP is indicated and the samePUSCH starting position is configured for carriers.

-   -   Option A: Without distinguishing between carriers and/or BWPs,        the UE may (randomly) select one specific CAP BW (i.e., a        representative CAP BW) from among assigned CAP BWs. The UE may        perform the Type 1 CAP only for the selected representative CAP        BW. The UE may perform the Type 2 CAP for the remaining CAP BWs        before the success of the Type 1 CAP for the representative CAP        BW. The UE may initiate simultaneous transmission in CAP BWs        that are determined to be idle. In this case, regarding the CAP        BWs where the simultaneous transmission is to be initiated,        transmission may be allowed only on a specific carrier when the        CAP is successful for at least all CAP BWs in the corresponding        carrier.

For example, it is assumed that for carrier #1, UL data transmission inone BWP, BWP #A including CAP BW #a/b is indicated and for carrier #2,UL data transmission in one BWP, BWP #C including CAP BW #c/d isindicated.

The UE may (randomly) select one CAP BW, CAP BW #c in carrier #2. CAP BW#c corresponds to the aforementioned representative CAP BW. The UE mayperform the Type 1 CAP only for selected CAP BW #c and perform the Type2 CAP for the remaining CAP BWs.

If CAP BW #a/c/d is determined to be idle when the Type 1 CAP succeeds,the UE may not initiate signal transmission in BWP #A since CAP BW #bincluded in BWP #A is busy. Since CAP BW #c/d included in BWP #B is allidle, the UE may initiate transmission in BWP #B. In other words, the UEmay perform UL transmission in BWP #B.

Option A may be suitable for the CWS adjustment described in Method 1.

-   -   Option B: The UE may (randomly) select one specific CAP BW        (i.e., a representative CAP BW) from among assigned CAP BWs only        within a carrier and/or a BWP. The UE may perform the Type 1 CAP        only for the representative CAP BW. The UE may perform the Type        2 CAP for the remaining CAP BWs before the success of the Type 1        CAP for the representative CAP BW and then initiate simultaneous        transmission in CAP BWs determined to be idle.

Option B may be suitable for the CWS adjustment described in Method 2and/or 3.

In the NR system, URLLC data may be preempted over eMBB data.Accordingly, a method by which a BS informs a UE of the region of theeMBB data that is not transmitted due to the preemption of the URLLCdata has been introduced in the NR system.

Specifically, a preemption indicator (PI) provided by group-common DCIand a flush indicator (FI) provided by a specific field in UE-specificDCI have been introduced in the NR system.

Particularly, the PI may indicate resource regions in which transmissionis performed and not performed through bitmap information obtained bydividing the frequency and time domains with specific granularity. TheBS may need to inform the UE whether data transmission is actuallyperformed or not due to the success or failure of the CAP on a U-band.

When the BS indicates whether the data transmission is actuallyperformed or not due to the success or failure of the CAP on the U-bandthrough the group-common DCI or UE-specific DCI, the (minimum)frequency-domain granularity may correspond to the CAP BW. Specifically,whether the data transmission is performed for each CAP BW may beindicated by the group-common DCI or UE-specific DCI. In the presentembodiment, a CAP BW may be replaced with the minimum BWP unit.

FIGS. 24A and 24B are diagrams illustrating BWP(s) applicable to thepresent disclosure.

Referring to FIGS. 24A and 24B, the following two options may beallowed.

-   -   Opt 1: Data is simultaneously transmitted in a plurality of        active BWPs.    -   Opt 2: Data is simultaneously transmitted in CAP BWs for which a        CAP is successful within one active BWP including multiple CAP        BWs.

In Both Opt 1 and Opt 2, data transmission may be allowed only incontinuous frequency bands.

Hereinafter, Opt 1 will be described in detail. When activation of aplurality of BWPs among four BWPs is allowed, data transmission may beallowed only for BWPs which are continuous in the frequency domain amongBWPs for which the CAP is successful.

For example, referring to FIG. 24A, when the CAP for BWPs 0, 1, and 3succeeds at the same time, data transmission may not be allowed for allBWPs 0, 1, and 3. The reason for this is that since BWPs 0, 1, and 3 arenot continuous in the frequency domain, additional requirements such asan RF filter for BWP 2 where no data is transmitted may be required.

Thus, the data transmission may be allowed for either BWP 0/1 or BWP 3,each of which is continuous. In this case, the BWP in which data is tobe transmitted may be selected according to a predetermined standard.The predetermined standard may be a predefined or configured rule.

For example, the data transmission may be performed in BWPs 0 and 1including more frequency-domain resources. Alternatively, the datatransmission may be performed in (continuous) BWPs including a specificBWP index.

The specific BWP index may include, for example, a higher index, a lowerindex, a specific configured index, a BWP index in which the randombackoff based CAP is performed, a BWP index having the highest or lowestCWS value at present, an edge BWP index over the entire band of a CC ora BWP, etc. When the specific BWP index is the highest index, the datatransmission may be performed in BWP 3.

Hereinafter, Opt 2 will be described in detail. When one active BWPincludes multiple CAP BWs, data transmission may be allowed only for CAPBWs which are continuous in the frequency domain among CAP BWs for whichthe CAP is successful.

For example, referring to FIG. 24B, when the CAP for CAP BWs 0, 1, and 3succeeds at the same time, data transmission may not be allowed for allCAP BWs 0, 1, and 3. The reason for this is that since CAP BWs 0, 1, and3 are not continuous in the frequency domain, additional requirementssuch as an RF filter for CAP BW 2 where no data is transmitted may berequired.

Thus, the data transmission may be allowed for either CAP BW 0/1 or CAPBW 3, each of which is continuous. In this case, the CAP BW in whichdata is to be transmitted may be selected according to a predeterminedstandard. The predetermined standard may be a predefined or configuredrule.

For example, the data transmission may be performed in CAP BWs 0 and 1including more frequency-domain resources. Alternatively, the datatransmission may be performed in (continuous) CAP BWs including aspecific CAP BW index. The specific CAP BW index may include, forexample, a higher index, a lower index, a specific configured index, aCAP BW index in which the random backoff based CAP is performed, a CAPBW index having the highest or lowest CWS value at present, an edge CAPBW index over the entire band of a CC or a BWP, etc. When the specificCAP BW index is the highest index, the data transmission may beperformed in CAP BW 3.

The present embodiment may be applied to both DL signal transmission atthe BS and UL signal transmission at the UE. In Opt 1 and Opt 2, the BWPmay be replaced with a frequency resource region for a scheduled PDSCHor PUSCH. Alternatively, in Opt 1 and Opt 2, the BWP may be replacedwith a CAP BW(s) resource region for a scheduled PDSCH or PUSCH.

In Opt 1 and Opt 2, the BWP may be replaced with frequency resources ina shared COT. The frequency resources in the shared COT refers to afrequency resource region occupied when a DL burst starts in aDL-initiated COT or a frequency resource region occupied when a UL burststarts in a UL-initiated COT.

The present embodiment may be allowed only for the UE (or some UEs)except the BS. That is, transmission in discontinuous frequency bands(on one carrier) may be allowed for the BS (and/or some UEs (withrelevant capability)), but the transmission in the discontinuousfrequency bands (on one carrier) may not be allowed for the UE (and/orsome UEs (with no relevant capability)).

The capability of the UE may be directed to the following options.

-   -   Opt 1: Association with (intra-band) UL carrier aggregation (CA)        capability

For example, when reporting 2-CC UL CA capability to the BS, the UE mayperform the CAP with a (digital) filter in every at least two CAPsub-bands. If a BWP of 40 MHz is activated for the UE, the correspondingUE may perform UL transmission (and DL reception) for every two CAPsub-bands in the active BWP.

Assuming that in a BWP of 80 MHz, two CAP sub-bands are defined as groupA and two other CAP sub-bands are defined as group B, the BS mayconfigure these CAP sub-band groups for the UE. The two CAP sub-bands ineach group may be continuous.

When the 80 MHz BWP is activated for the UE, the UE may perform ULtransmission and/or DL reception in the CAP sub-bands of one group orthe CAP sub-bands of the two groups depending on CAP results per CAPsub-band even though the UE is scheduled to transmit in both group A andgroup B.

If the corresponding UE is configured with 2-CC CA and the 40 MHz BWP isactivated for each CC, the UL transmission and/or DL reception may beperformed only when the CAP is successful for all CAP sub-bands for eachBWP.

-   -   Opt 2: The UE reports the number of available CAP sub-bands or        the number of frequency fragments to the BS.

Here, the available CAP sub-band or frequency fragment may exist foreach carrier/BWP (or in a band of 5/6 GHz).

This option may not be related to the UL CA capability of the UE. Areport according to Opt 1 and/or Opt 2 may be provided throughcapability signaling.

For example, when the UE is capable of managing two CAP sub-bands, theUE may perform the CAP with a (digital) filter in every at least two CAPsub-bands.

The UE may report the UE capability of managing two CAP sub-bands to theBS. When a BWP of 40 MHz is activated for the UE, the UE may assume thatthe UE is capable of performing UL transmission (and DL reception) inevery two CAP sub-bands in the active BWP.

Assuming that in a BWP of 80 MHz, two CAP sub-bands are defined as groupA and two other CAP sub-bands are defined as group B, the BS mayconfigure these CAP sub-band groups for the UE. The two CAP sub-bands ineach group may be continuous.

When the 80 MHz BWP is activated for the UE, the UE may perform ULtransmission and/or DL reception in the CAP sub-bands of one group orthe CAP sub-bands of the two groups depending on CAP results per CAPsub-band even though the UE is scheduled to transmit in both group A andgroup B.

If the corresponding UE is configured with 2-CC CA and the 40 MHz BWP isactivated for each CC, the UL transmission and/or DL reception may beperformed only when the CAP is successful for all CAP sub-bands for eachBWP.

As described above, the present disclosure relates to a method for aUE/BS to transmit a signal in a wireless communication system supportingU-bands. Such a UE/BS may be referred to as a transmission node.

FIG. 25 is a flowchart illustrating a UE operation method in a U-bandapplicable to the present disclosure.

Referring to FIG. 25, a UE may perform a CAP for a plurality offrequency BW units included in an active BWP (S2501). The active BWP mayhave a frequency BW greater than a frequency BW unit. The frequency BWunit may be equivalent to the aforementioned CAP BW or the BWcorresponding thereto.

The UE may configure a data signal based on a frequency BW greater thana single frequency BW unit (S2503). That is, the data signal may bemapped to a frequency resource with a BW greater than the CAP BW. Forexample, the frequency resource to which the data signal is mapped mayhave a BW greater than 20 MHz. In addition, the frequency BW greaterthan the single frequency BW unit may be equivalent to the active BWP orthe BW corresponding thereto.

The data signal may be configured according to a frequency-first mappingmethod. Specifically, the data signal may be mapped in the frequency BWgreater than the single frequency BW unit according to thefrequency-first mapping method. The data signal may include a pluralityof blocks defined based on a plurality of frequency intervals and atleast one time interval. Frequency-first mapping may be performed on ablock basis. Here, the time interval may correspond to a slot, and theblock may correspond to a slot group including at least one slot.

The UE may transmit the configured data signal in the U-band (S2505). Inthis case, the UE may transmit the data signal based on the CAP.Specifically, the UE may transmit the data signal in at least onefrequency BW unit determined to be idle by the CAP. In addition, the UEmay defer transmission of (a part of) the data signal mapped to at leastone frequency BW unit determined to be busy by the CAP (throughpuncturing). In this case, the UE may transmit information on the atleast one frequency BW unit determined to be busy. The deferred datasignal may be transmitted in at least one slot after a slot in which thedata signal is transmitted in the at least one frequency BW unitdetermined to be idle.

The data signal may include a TB with a different RV for each of theplurality of frequency BW units. Different RVs may have different RVindices. An RV index may be determined by scheduling DCI. Alternatively,the RV index may be determined by a function related to the plurality offrequency BW units.

The UE may transmit a DM-RS based on the CAP. In this case, thetransmission start time of the DM-RS may be determined based on thestart time of the CAP and the transmission start time of the datasignal. Alternatively, the transmission start time of the DM-RS may bedetermined by shifting the location of a symbol to which the DM-RS ismapped based on the CAP.

FIG. 26 is a flowchart illustrating a BS operation method in a U-bandapplicable to the present disclosure.

Referring to FIG. 26, a BS may perform a CAP for a plurality offrequency BW units included in an active BWP (S2601). The active BWP mayhave a frequency BW greater than a frequency BW unit. The frequency BWunit may be equivalent to the aforementioned CAP BW or the BWcorresponding thereto.

The BS may configure a data signal based on a frequency BW greater thana single frequency BW unit (S2603). That is, the data signal may bemapped to a frequency resource with a BW greater than the CAP BW. Forexample, the frequency resource to which the data signal is mapped mayhave a BW greater than 20 MHz. In addition, the frequency BW greaterthan the single frequency BW unit may be equivalent to the active BWP orthe BW corresponding thereto.

The data signal may be configured according to a frequency-first mappingmethod. Specifically, the data signal may be mapped in the frequency BWgreater than the single frequency BW unit according to thefrequency-first mapping method. The data signal may include a pluralityof blocks defined based on a plurality of frequency intervals and atleast one time interval. Frequency-first mapping may be performed on ablock basis. Here, the time interval may correspond to a slot, and theblock may correspond to a slot group including at least one slot.

The BS may transmit the configured data signal in the U-band (S2605). Inthis case, the BS may transmit the data signal based on the CAP.Specifically, the BS may transmit the data signal in at least onefrequency BW unit determined to be idle by the CAP. In addition, the BSmay defer transmission of (a part of) the data signal mapped to at leastone frequency BW unit determined to be busy by the CAP (throughpuncturing). In this case, the BS may transmit information on the atleast one frequency BW unit determined to be busy. The deferred datasignal may be transmitted in at least one slot after a slot in which thedata signal is transmitted in the at least one frequency BW unitdetermined to be idle.

The data signal may include a TB with a different RV for each of theplurality of frequency BW units. Different RVs may have different RVindices. An RV index may be determined by scheduling DCI. Alternatively,the RV index may be determined by a function related to the plurality offrequency BW units.

The BS may transmit a DM-RS based on the CAP. In this case, thetransmission start time of the DM-RS may be determined based on thestart time of the CAP and the transmission start time of the datasignal. Alternatively, the transmission start time of the DM-RS may bedetermined by shifting the location of a symbol to which the DM-RS ismapped based on the CAP.

Since examples of the above-described proposal method may also beincluded in one of implementation methods of the present disclosure, itis obvious that the examples are regarded as a sort of proposed methods.Although the above-proposed methods may be independently implemented,the proposed methods may be implemented in a combined (aggregated) formof a part of the proposed methods. A rule may be defined such that theBS informs the UE of information as to whether the proposed methods areapplied (or information about rules of the proposed methods) through apredefined signal (e.g., a physical layer signal or a higher-layersignal).

4. Device Configuration

FIG. 27 is a block diagram illustrating the configurations of a UE and aBS for implementing the proposed embodiments. The UE and the BSillustrated in FIG. 27 operate to implement the embodiments of theafore-described method of transmitting and receiving a signal in anunlicensed band.

A UE 1 may act as a transmission end on a UL and as a reception end on aDL. A BS (eNB or gNB) 100 may act as a reception end on a UL and as atransmission end on a DL.

That is, each of the UE and the BS may include a Transmitter (Tx) 10 or110 and a Receiver (Rx) 20 or 120, for controlling transmission andreception of information, data, and/or messages, and an antenna 30 or130 for transmitting and receiving information, data, and/or messages.

Further, each of the UE and the BS includes a processor 40 or 140 forimplementing the afore-described embodiments of the present disclosure.The processor 40 or 140 may be configured to perform the foregoingdescribed/proposed procedures and/or methods by controlling the memory50 or 150 and/or the Tx 10 or 110 and/or the Rx 20 or 120.

For example, the processor 40 or 140 includes a communication modemdesigned to implement wireless communication technologies (e.g., LTE andNR). The memory 50 or 150 is coupled to the processor 40 or 140, andstores various types of information related to operations of theprocessor 40 or 140. For example, the memory 50 or 150 may storesoftware code including instructions for performing all or part ofprocesses controlled by the processor 40 or 140 or theafore-described/proposed procedures and/or methods. The Tx 10 or 110and/or the Rx 20 or 120 is coupled to the processor 40 or 140 andtransmits and/or receives a wireless signal. The processor 40 or 140 andthe memory 50 or 150 may be part of a processing chip (e.g., system onchip (SoC)).

A processor of a communication device for performing BWP operationsaccording to the present disclosure may operate as follows bycontrolling a Tx, an Rx, and/or a memory.

The processor may be configured to transmit and received information ona set of BWPs configured on carrier(s). For example, the processor ofthe BS may be configured to configure for the UE a BWP set on carrier(s)and transmit information on the BWP set configured on the carrier(s).The processor of the UE may be configured to receive such information.

The processor may be configured to perform a CAP for performingcommunication in a U-band.

The processor may be configured to perform BWP-related operations basedon CAP results. The BWP-related operations may include the active BWPindication, the DL-UL COT sharing, the control/data channelgeneration/transmission, etc. according to the embodiments of thepresent disclosure.

The BS 100 including the communication device may be configured tocontrol the processor 140, the Tx 110, and the Rx 120 to perform the CAPfor transmitting a DL signal in the U-band and transmit a DL Tx burstincluding an initial signal and a PDCCH in the U-band based on the CAP.The PDCCH included in the DL Tx burst may be transmitted to the UE witha predetermined periodicity while the DL Tx burst is transmitted.

The Tx and Rx of the UE and the BS may perform packetmodulation/demodulation for data transmission, high-speed packet channelcoding, OFDM packet scheduling, TDD packet scheduling, and/or channelmultiplexing. Each of the UE and the BS of FIG. 27 may further include alow-power radio frequency/intermediate frequency (RF/IF) module.

Meanwhile, the UE may be any of a Personal Digital Assistant (PDA), acellular phone, a Personal Communication Service (PCS) phone, a GlobalSystem for Mobile (GSM) phone, a Wideband Code Division Multiple Access(WCDMA) phone, a Mobile Broadband System (MBS) phone, a hand-held PC, alaptop PC, a smart phone, a Multi-Mode Multi-Band (MM-MB) terminal, etc.

The smart phone is a terminal taking the advantages of both a mobilephone and a PDA. It incorporates the functions of a PDA, that is,scheduling and data communications such as fax transmission andreception and Internet connection into a mobile phone. The MB-MMterminal refers to a terminal which has a multi-modem chip built thereinand which can operate in any of a mobile Internet system and othermobile communication systems (e.g. CDMA 2000, WCDMA, etc.).

Embodiments of the present disclosure may be achieved by various means,for example, hardware, firmware, software, or a combination thereof.

In a hardware configuration, the methods according to exemplaryembodiments of the present disclosure may be achieved by one or moreApplication Specific Integrated Circuits (ASICs), Digital SignalProcessors (DSPs), Digital Signal Processing Devices (DSPDs),Programmable Logic Devices (PLDs), Field Programmable Gate Arrays(FPGAs), processors, controllers, microcontrollers, microprocessors,etc.

In a firmware or software configuration, the methods according to theembodiments of the present disclosure may be implemented in the form ofa module, a procedure, a function, etc. performing the above-describedfunctions or operations. A software code may be stored in the memory 50or 150 and executed by the processor 40 or 140. The memory is located atthe interior or exterior of the processor and may transmit and receivedata to and from the processor via various known means.

Those skilled in the art will appreciate that the present disclosure maybe carried out in other specific ways than those set forth hereinwithout departing from the spirit and essential characteristics of thepresent disclosure. The above embodiments are therefore to be construedin all aspects as illustrative and not restrictive. The scope of thedisclosure should be determined by the appended claims and their legalequivalents, not by the above description, and all changes coming withinthe meaning and equivalency range of the appended claims are intended tobe embraced therein. It is obvious to those skilled in the art thatclaims that are not explicitly cited in each other in the appendedclaims may be presented in combination as an embodiment of the presentdisclosure or included as a new claim by a subsequent amendment afterthe application is filed.

The present disclosure is applicable to various wireless access systemsincluding a 3GPP system, and/or a 3GPP2 system. Besides these wirelessaccess systems, the embodiments of the present disclosure are applicableto all technical fields in which the wireless access systems find theirapplications. Moreover, the proposed method can also be applied tommWave communication using an ultra-high frequency band.

What is claimed is:
 1. A method performed by an apparatus operating in awireless communication system, the method comprising: obtaining anuplink (UL) resource comprising a plurality of frequency bandwidth unitsof a carrier bandwidth; and performing a channel access procedure (CAP)for an UL transmission configured in the UL resource, wherein the CAP isperformed on the plurality of frequency bandwidth units, wherein each ofthe plurality of frequency bandwidth units comprises resource blocks(RBs) that are contiguous in frequency, wherein a bandwidth part (BWP)is configured in the carrier bandwidth, and wherein a unit to configurethe BWP is limited to a frequency bandwidth unit among the plurality offrequency bandwidth units.
 2. The method of claim 1, wherein the ULresource is obtained based on downlink control information (DCI)scheduling the UL transmission.
 3. The method of claim 1, furthercomprising: receiving information related to configuration regarding theBWP, wherein the BWP is not configured to partially comprise respectivefrequency bandwidth unit included in the plurality of frequencybandwidth units.
 4. The method of claim 3, wherein the BWP is configuredto completely comprise respective frequency bandwidth unit included inthe plurality of frequency bandwidth units.
 5. The method of claim 1,further comprising: transmitting a demodulation reference signal(DM-RS), wherein a transmission start time of the DM-RS is determinedbased on a predetermined method, and wherein the predetermined methodcomprises at least one of: the transmission start time of the DM-RSbeing determined based on a start time of the CAP and a transmissionstart time of the UL transmission; or the transmission start time of theDM-RS being determined by shifting, based on the CAP, a location of asymbol to which the DM-RS is mapped.
 6. The method of claim 1, whereinthe UL transmission comprises a transmission block with a differentredundancy version (RV) for each of the plurality of frequency bandwidthunits.
 7. The method of claim 6, wherein different RVs are related todifferent RV indices that are determined based on at least one of: (i)downlink control information (DCI) scheduling the UL transmission on theUL resource, or (ii) a function related to the plurality of frequencybandwidth units.
 8. The method of claim 1, wherein at least a part ofthe UL transmission is not transmitted based on failing to access atleast one frequency bandwidth unit among the plurality of frequencybandwidth units according to the CAP.
 9. The method of claim 8, whereinthe UL transmission is transmitted based on success to access all of theplurality of frequency bandwidth units according to the CAP, and whereinthe UL transmission is not transmitted based on failing to access the atleast one frequency bandwidth unit according to the CAP.
 10. Anapparatus configured to operate in a wireless communication system, theapparatus comprising: a memory; and at least one processor coupled withthe memory, wherein the at least one processor is configured to: obtainan uplink (UL) resource comprising a plurality of frequency bandwidthunits of a carrier bandwidth; and perform a channel access procedure(CAP) for an UL transmission configured in the UL resource, wherein theCAP is performed on the plurality of frequency bandwidth units, whereineach of the plurality of frequency bandwidth units comprises resourceblocks (RBs) that are contiguous in frequency, wherein a bandwidth part(BWP) is configured in the carrier bandwidth, and wherein a unit toconfigure the BWP is limited to a frequency bandwidth unit among theplurality of frequency bandwidth units.
 11. The apparatus of claim 10,wherein the UL resource is obtained based on downlink controlinformation (DCI) scheduling the UL transmission.
 12. The apparatus ofclaim 10, wherein the at least one processor is further configured to:receive information related to configuration regarding the BWP, whereinthe BWP is not configured to partially comprise respective frequencybandwidth unit included in the plurality of frequency bandwidth units.13. The apparatus of claim 12, wherein the BWP is configured tocompletely comprise respective frequency bandwidth unit included in theplurality of frequency bandwidth units.
 14. The apparatus of claim 10,wherein the at least one processor is further configured to: transmit ademodulation reference signal (DM-RS), wherein a transmission start timeof the DM-RS is determined based on a predetermined method, and whereinthe predetermined method comprises at least one of: the transmissionstart time of the DM-RS being determined based on a start time of theCAP and a transmission start time of the UL transmission; or thetransmission start time of the DM-RS being determined by shifting, basedon the CAP, a location of a symbol to which the DM-RS is mapped.
 15. Theapparatus of claim 10, wherein the UL transmission comprises atransmission block with a different redundancy version (RV) for each ofthe plurality of frequency bandwidth units.
 16. The apparatus of claim15, wherein different RVs are related to different RV indices that aredetermined based on at least one of: (i) downlink control information(DCI) scheduling the UL transmission on the UL resource, or (ii) afunction related to the plurality of frequency bandwidth units.
 17. Theapparatus of claim 10, wherein at least a part of the UL transmission isnot transmitted based on failing to access at least one frequencybandwidth unit among the plurality of frequency bandwidth unitsaccording to the CAP.
 18. The apparatus of claim 17, wherein the ULtransmission is transmitted based on success to access all of theplurality of frequency bandwidth units according to the CAP, and whereinthe UL transmission is not transmitted based on failing to access the atleast one frequency bandwidth unit according to the CAP.